Formula 1 tyre supplier Pirelli has revealed they will introduce at least one new soft compound to their current range in 2018, with potentially as many as eight being homologated for next season.

In the wake of the new rules for 2017, the Italian manufacturer not only produced wider tyres for this year but also ended the intentional high degradation of their tyres, which they introduced when they arrived in 2011.

For some, however, this year's rubber has been too hard and durable with most races only requiring one stop and the Hard compound itself only being used at a single race back in Spain.

It is already understood the 2018 compounds are to be more aggressive with a potential two-step jump softer compared to 2017, meaning the current Soft tyre could become the Hard next season.

That is to coincide with an additional compound being introduced which will be even softer than the current UltraSoft, which was brought in, in 2016. Pirelli has asked the fans to name the new tyre, which will feature the pink-stripes used in Austin, with the choices of MegaSoft, ExtremeSoft of HyperSoft put forward.

It is likely this tyre will only feature at circuits with very low degradation or grip, such as Monaco, Sochi and Singapore but may not be the only new compound as Pirelli Motorsport boss Mario Isola explained.

"We will have a range that is more usable, including the [new] hard, so we'll have five compounds that are usable. We want to increase this range and this is the reason why probably we are going to homologate more than five," he said.

"If you exaggerate the number it looks like you are confused. So we need to choose a number that is enough to give us the flexibility [but is] not too big."

It was hoped Pirelli could continue testing their various compounds this week in Brazil before the two days of running was cancelled on safety grounds, after the attacks last weekend but the supplier will get the chance to gather data at the post-season test in Abu Dhabi in two weeks time.

Haas F1 Team Principal Guenther Steiner has once again voiced his unhappiness with the consistency of stewards decision after Romain Grosjean was penalised for the first lap collision with Esteban Ocon in Brazil.

The two Frenchman went side-by-side entering Ferradura with the Force India driver trying to sweep around the outside but his countryman would lose the rear of the car making contact with Ocon's car and sending both into the run-off area.

The incident marked the 21-year-old's first retirement in F1 after 27 races and saw Grosjean given a 10-second time penalty plus two penalty points and it was the severity of the punishment which most irritated Steiner when speaking after the race, comparing it to Lance Stroll's for blocking the former Lotus driver in qualifying in Austin.

"I share my surprise more in the verdict," he said. "It doesn't influence our result here, we were done by then and we took it as a test session, nothing else, but he got two penalty points for a racing accident in my opinion.

"Stroll got one penalty point when the speed difference was 140km/h and that was pretty dangerous, it doesn't get any better by the way, the more I mention it I think it gets worse."

Romain himself was unhappy he was penalised at all by the stewards, claiming he was the victim of contact too but did apologise to Ocon for what happened.

"Not the race we were hoping for," he said in a video posted on social media. "I'm sorry for the contact with Esteban, I was touched strongly from behind, I believe I had a puncture from there so I lost the car and he was on the outside.

"It's to me a racing incident, in my opinion, I'm really struggling to understand the penalty, which was super harsh. It is what it is and we have to move on."

It is the latest penalty given to him by the stewards after being deemed guilty of going off track and gaining an advantage in a battle with Fernando Alonso in Mexico, to which Steiner claimed the Spaniard only has to complain to get his own way.

He also joined the call for permanent stewards in F1 to improve consistency with the events of Sao Paulo not changing his mind.

"Not as far as I know. It hasn't shown any progress. So it's very difficult," he claimed.

Team Principal Christian Horner has denied his recent comments suggesting Max Verstappen should "build" the Red Bull team around him going forward, was a snub towards teammate Daniel Ricciardo.

The comments came as the Briton looked to reassure the Dutchman that the Milton Keynes outfit would be the right place to try and beat Lewis Hamilton and Sebastian Vettel to the Formula 1 title. It appears the words stuck too, as prior to the United States Grand Prix, Verstappen would sign a new contract extension until 2020.

At the same time, however, it raised suspicions as to whether Red Bull was starting to push the 20-year-old forward as the lead driver ahead of Ricciardo, who is out of contract after 2018 and has already made it clear he will wait to assess his options.

Talking to Motor Sport magazine though, Horner insisted he did not mean it to belittle the importance of the five-time F1 winner to the team.

"What actually I'm referring to is within his engineering group with the people he (Verstappen) is working with," he claimed, "in the same way that Ricciardo has that confidence in the people around him in his garage and to make his feedback very clear in terms of what he wants from the car.

"Fortunately, the way the two drivers drive the car is very similar, their set-ups are very similar. It's not like as a team we have a left or right to choose. What works for one 99 percent of the time works for the other in how we progress the car."

Horner has made his feelings clear that he wants the 28-year-old to sign the same deal until the end of 2020 as Verstappen, stating the two together could well be Red Bull's most talented line-up in their 12 years on the grid.

"I feel that Max and Daniel represent our best ever pairing in Formula 1 and are currently, probably the best driver pairing on the grid," he said. "So it’s my priority to make sure we retain that, at least until 2020."

On Ricciardo, he continued by proclaiming the man from Perth as F1's best overtaker following his latest comeback through the field in Brazil on Sunday.

"He came past us on the pit wall and you thought 'he should get close into Turn 1', and then he's past!” Horner said. “He brakes so late, so deep. He's really mastered that now. That's why for me he's one of the best overtakers out there, if not the best.”

Max Verstappen believes Red Bull's engine supplier Renault has run out of parts for their 2017 engines such has been the unreliability at the end of the season.

His claim comes as both he and teammate Daniel Ricciardo, who suffered two engine-related retirements in Austin and Mexico, were forced to race with reduced power last weekend in Brazil to ensure their power units can make it to the end of the year.

It also follows a dispute on Saturday between the French manufacturer and junior team Toro Rosso, which Team Principal Franz Tost suggested his team's recent engine problems could be competition-related in response claims by Renault Sport Managing Director that the issues may be associated with how it is installed in their car.

That led to Renault threatening to withhold engines from the Italian team until the end of the season and required Red Bull Motorsport advisor Helmut Marko's interference to diffuse the situation.

While Verstappen's comments are unrelated to that incident, it does highlight a frustration between customer and supplier which has been the case throughout the year.

"On the one hand, I can understand that [Renault is running low on engines]," the 20-year-old is quoted by Holland's De Telegraaf. "But on the other, if you have so many problems with reliability during the season, then as a supplier you have to do what you can to have enough parts on the shelf. That just seems logical. It's frustrating but we also have to accept it."

The impact of the measures put in place at Interlagos was Red Bull, who have had a resurgence late in the year with the Dutchman winning twice in Malaysia and Mexico was once again floundering as the third-best team behind Mercedes and Ferrari.

"After four very good races it's a bit of a pity, but you also have to be realistic," Verstappen added. "The car itself was good."

Offering another view, Mercedes Non-Executive Chairman Niki Lauda claims the recent engine problems for his team's rivals backs the decision the German manufacturer took to ensure optimum reliability.

"As we had a car with erratic performance, we could not afford any engine problems," he told Italy's La Gazzetta dello Sport.

"So [Motorsport boss] Toto [Wolff] and I asked [Mercedes engine boss] Andy Cowell what was more important - to find a tenth or to remain reliable? After all, you cannot win a championship without reliability.

"Ferrari and Renault privileged their search for performance and lost Grands Prix."

Mercedes Motorsport boss Toto Wolff has defended the performance of Valtteri Bottas during the Brazilian Grand Prix after losing out to Sebastian Vettel and also when compared to the result of teammate Lewis Hamilton.

The Finn was overtaken into Turn 1 at the start by the Ferrari driver and could never get back into a strong enough position to challenge back for the victory despite the gap between the top two never exceeding three seconds.

In contrast, Hamilton, who started from the pit-lane after a crash in qualifying, was within three seconds of Bottas by the chequered flag as he finished fourth after a rapid recovery through the field.

Wolff would admit a feeling the newly crowned world champion could have won had his tyres not worn in the closing laps, but claims evaluations between the two drivers were unfair given the different type of battle each one faced.

"I think Lewis the whole year has been rock and roll, and Valtteri has recovered slowly but still needs the tick of a killer," said the Austrian suggesting Bottas had been a little passive.

"But you must not underestimate that in traffic against the Ferraris it was pretty difficult," he continued. "You can see that at the end, when Ferrari switched the engine on, there was not much difference between the cars. Therefore you cannot expect easy overtakes."

The nearest the 28-year-old came was in the pit-stop phase when Mercedes attempted the undercut, but even Wolff admitted: "It was a little move of desperation because we couldn't get too close, and we knew that probably it lacked half a second - but nevertheless we gave it a go and the result was as expected."

One critic who wasn't so forgiving was outspoken 1997 world champion Jacques Villeneuve, who was far from impressed by what Bottas did.

“When you see what the Mercedes was capable of, you just have to look at Lewis and Bottas wasn’t up to pace. It’s embarrassing for Bottas," he told Motorsport.com.

“Lewis finished around three seconds behind him when he started from the pits, it’s embarrassing. He simply is not on the pace of Hamilton. It’s been like that all year that’s his level. Which is a good number two.”

Williams Technical Director Paddy Lowe is keeping his cards very close to his chest over whether Robert Kubica will be driving with the Grove team in 2018, insisting they remain "open-minded".

Over the weekend rumours intensified that the Pole, who recently completed two test days with Williams at Silverstone and the Hungaroring, will be the man to replace Felipe Massa next season, with French broadcaster Canal + going further by claiming a deal has been signed.

Just over a week ago Massa confirmed he would be retiring at the end of the season, allowing him to say farewell to his fans at Interlagos last weekend but with other names like reserve driver Paul di Resta, who completed the same tests as Kubica, Sauber's Pascal Wehrlein and Red Bull outcast Daniil Kvyat all linked, Lowe insists no decision has yet been taken.

"We're open-minded," he was quoted by Sports Mole. "The important thing is that we have the best lineup next year in terms of performance."

It is also reported Kubica's next appearance for Williams will come at the post-season test in Abu Dhabi following the season finale but again on that, the former Mercedes chief wasn't making anything official.

"We are considering what the best options are for the two days of tyre testing, and Kubica is definitely a strong option," he claimed.

The 2007 Canadian Grand Prix winner is looking to make a remarkable return to F1 after seeing his first stint ended by a severe rally crash before the 2011 season, leaving the 32-year-old with restricted movement in his right arm.

His first effort came with his former team Renault, driving at the mid-season test in Hungary but attention switched to Williams when the Enstone team managed to secure Carlos Sainz as part of the engine swap deal between Toro Rosso and McLaren.

Antonio Giovinazzi believes he is now the most prepared he has ever been to compete in Formula 1 after learning from his mistakes at the Chinese Grand Prix at the start of the year.

The young Italian stepped in for an injured Pascal Wehrlein at Sauber in the first two races and would impress at the opening round in Australia, but two crashes in qualifying and the race in tricky conditions in Shanghai left a bad impression with Wehrlein returning from the next race in Bahrain.

Fulfilling his role as Ferrari third driver since, Giovinazzi has also completed a number of Practice 1 outings with Haas this season with the Scuderia wanting their American technical partners to take on the 2016 GP2 runner-up for next year, though that likelihood appears unlikely.

If he did get the chance, however, is sure he would be in a much stronger position to meet the high expectations many have of the 23-year-old.

"This year gave me more than I expected," Giovinazzi told Italy's La Gazzetta Dello Sport. "I do not hide that after a great year in GP2, I felt ready to race a full season in F1, that's how it is. But now I feel even much more prepared than I did last winter."

The experience from that weekend in Shanghai was one which he admits changed a lot of his perceptions.

"In Australia, I had a great time but China was the worst weekend of my entire career as a driver," Antonio said. "It happened to me on the most important stage when I had all the media pressure on me. Critics attacked me a lot.

"I understand better that you always have to keep your feet on the ground. I do not want to say that it went to my head, but perhaps in China, I set goals that were bigger than I could do at that time.

"You have to be aware of your limitations and that everything comes to you in time but the disappointment has helped me to grow."

An alternative to Haas for 2018 could be Sauber, where fellow Ferrari member and F2 champion Charles Leclerc is expected to be confirmed, indeed, Team Principal Fred Vasseur is targeting an announcement of the Swiss team's line-up at the season finale.

"We will do the announcement, I hope, in Abu Dhabi," Vasseur said. "I think Charles is doing a good job. The situation in FP1 is not an easy one because the first target is to avoid crashing, and by the way that he’s consistent, and he always shows a strong pace, he’s doing a good job."

Formula 1 owners Liberty Media have called for action to address security concerns raised after a number of teams were involved in armed robberies outside the Interlagos circuit during the Brazilian Grand Prix weekend.

On Friday evening, Mercedes personnel were held at gunpoint outside the Sao Paulo track and their valuables were taken, though additional measures were put in place, further reported violent incidents on Williams and Pirelli took place over the last two days.

As a result, the Italian tyre supplier cancelled a planned test in with McLaren this week citing an "unnecessary risk" and, though security has often been a problem over the years with team items stolen and Jenson Button a victim of an attempted attack several years, the scale of the situation this year has raised questions over the safety of the race.

"We will once more press on the promoter this [security] is a higher priority," a spokesman for Liberty told the UK's Standard Sport.

"The promoter is essentially in charge of the circuit and the local authorities where we race are in charge of the area outside the circuit but that’s not saying that we’re doing away with any responsibility.

"We can’t, say, affect police rotas. Whether we should have races in cities with difficulties like that is something that is a broader question. We are extremely concerned and are evaluating through the security company we work. We will report back to promoters — we’re not standing idle.

"We have our own security team that travels with us and we are actively involved, but we cannot be experts in every city we go to. We have a year between now and the next race to get it sorted, and we would be extremely disappointed if things have not been looked at," the spokesperson added.

Commenting on what occurred, Sao Paulo Mayor Joao Doria was disappointed but insisted the Brazilian city isn't the only place such incidents occur.

"What has happened cannot be justified but I've seen worse cases at other race tracks," he told the DPA news agency. "It was the first time we had a case of such seriousness.

"These are regrettable circumstances, but they can occur in any country," he added to Brazil's Globo.

Despite reported interest in neighbouring Argentina to return to F1, uncertainty surrounding Interlagos, which is set to be sold in the coming months, and the prospect of no Brazilian drivers on the grid in 2018, Mayor Doria insisted the future of the race is secure.

"We have a contract until 2020 and whoever purchases the circuit must respect it. After that, we hope we can renew for another 10 years," he said.

On whether the incidents would impact negotiations, he replied: "No, because while bad things happening is unfortunate, it also means you make things better in the future."

Red Bull Team Principal Christian Horner has downplayed the significance of the negative reaction from manufacturers to the proposals put forward for changes to the engine formula from 2021.

Renault, Mercedes and Ferrari all aired concerns over the ideas, which called for an increase in revs, no MGU-H in favour of a more powerful MGU-K and greater conformity across the different designs.

The Italian team went even further threatening to quit Formula 1 if the vision put forward by owners Liberty Media didn't meet with that of the bosses at Maranello, but Horner doubts there is much gumption behind that threat and the other comments, given how closely manufacturers have been involved in the process.

"There's been consultation with all the manufacturers," he told Autosport in Brazil. "I don't think there was anything that was presented that was a surprise, I'd heard it all before, either in individual consultation or through what had been discussed in the media.

"What seemed to upset a couple of manufacturers was the press release that came out following the meeting - I think they were upset that it was presented as a fait accompli (a set proposal with no room for compromise).

"Inevitably there'll be some filibustering and I think it's obvious that the commercial side of the proposition is being linked to the technical," Horner added, suggest power games were at play. "So there's a lot of leveraging that inevitably is going on.

"You can see that happening. With Ferrari and Mercedes, sometimes it's hard to recognise which one is which, or who's running which team, but they are particularly aligned."

The Red Bull boss has offered his support, along with several manufacturers considering an entry in 2021 to the idea put forward and he backs Liberty to stand their ground in the inevitable fight that is looming between F1 bosses and the main power players of the last 20 years or so.

"F1 has a habit of conducting its business through the media, it's all part of the theatre and show that is F1, and part of the intrigue," the Briton suggested

"I've been quite impressed with the way they (Liberty) have handled things so far, that they're not rolling over, there are no clandestine discussions and meetings going. What their goals and objectives are is very, very clear."

Finally, Horner talked up the changes believing though they don't necessarily meet the desire of everyone, the compromise is one that addresses several issues with the sport today.

"I actually felt what was presented was actually a pretty sensible set of proposals and ideology of moving forward," he said. "Under Ross [Brawn], whose approach has always been to do the analysis and research prior to setting off on a journey, for the first time that I can remember I feel that they've done that.

"They've recruited some good specialists that have done the analysis, from what I saw everything that was presented had a clear and sensible logic behind it.

"I think ultimately the consumer, ie the fan, will end up with a better product - a better sound, more marginal performance differential, a sporting element with the overtake button. I didn't see anything that didn't address the fundamental issues that we are currently experiencing."

Sebastian Vettel was pleased to let Ferrari put the recent problems behind them by beating Valtteri Bottas to claim victory at the Brazilian Grand Prix, his first since August.

The German made the decisive move on the Mercedes into Turn 1 at the start and would produce a faultless performance to maintain a small but comfortable margin en route to his fifth win of the season.

Commenting on the key moment, Vettel admitted he was surprised by just how poor Bottas' start was but was pleased to take advantage.

“Initially I had a very good getaway and then I had a bit of wheelspin and thought I’d missed my chance,” he claimed. “I think Valtteri was struggling even more off the line so I had a chance to squeeze down the inside, I think I surprised him a bit.

“It was crucial after that as we were pushing more. After the Safety Car, I was pushing to try and get a bit of a gap and control the race from there.”

The win comes as Ferrari had been doing some soul-searching in the wake of a stretch of races that had been hampered by reliability, allowing Lewis Hamilton to claim the championship, and the continued improvements by Red Bull, who have out-scored the Scuderia since the summer break.

“[I’m] really happy for all the guys in the team back home in Maranello,” he said. “It has been a tough couple of weeks for us so nice to get it today and have both cars up there.

“It has been a tough race I spoke with Valtteri and the pace was all more or less the same, no room for mistakes,” the 30-year-old added.

What also helped was Hamilton not being at the front of the grid after his crash in qualifying. Such was the Briton's pace in his recovery, however, he was catching Vettel by over a second per lap on the alternate strategy but the four-time world champion was never concerned by the 32-year-old, who would finish fourth.

“Not really,” he said. "Obviously I saw him pitting just in front of me so he had to make up that pit stop but I think it's not the first time this year that we've seen that the mirror strategy has some advantages.

“It's not very attractive if you're starting in the front but it can be very attractive when you're out of position which he was. So you obviously have an advantage.

"I think the track ramped up in the end and the Supersoft was clearly the faster tyre but overall it's fair to say that Lewis was very quick,” Vettel added. “I think for us, as I said yesterday, it was nice to see that we were that close in qualifying trim.”