Formula 1 motorsport boss Ross Brawn insists fans will only return to the grandstands at Grands Prix when it's considered safe to do so.

While the 2020 season is finally set to get underway with at least eight races in 10 weeks starting in Austria next month, the cars will be driving around largely empty racetracks but for marshals and other key personnel at their stations.

That is putting considerable financial stress on F1 rights holder Liberty Media, who have had to renegotiate deals with every race set to take place behind closed doors.

But while some venues have expressed a desire to hold normal events with fans, and F1 itself has said they hope some later rounds can see them return, Brawn isn't banking on that happening any time soon.

"We won't rush that," he told an FIA eConference this week. "I think some of the later European races are optimistic, but I think we would rather not plan on that.

"I think when we go to the flyaway races, we can start to hope that we will have fans, but even that's not absolutely guaranteed. I think to have the race in a safe and secure environment is critical.

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"We're going around the world, we can't have a problem in one country that stops us from going to other countries. We'll progress slowly on that front.

"The fans for us are critical," Brawn noted. "We do want to see them as they do add a lot of atmosphere. I think we'll take that very gradually, but we don't want to jump in and then have to jump out again when we find a problem.

"The situation is different throughout the world. I think the fact that we were prepared to accept closed races in the early part of the season gave us more opportunity.

"That's not ideal, it's not ideal for any sport because the fans are such a crucial part of it. But we felt going racing and broadcasting racing and engaging the fans with racing in what ways we could was still much more desirable than doing nothing."

As it stands, there is increasing uncertainty over F1's annual trip to the Americas, where the rise in coronavirus cases remains strong, and only China appears a likely destination in Asia.

That means more European circuits like Mugello, Portimao, Hockenheim and Imola are being tipped to join the calendar in order to reach the target of at least 15 races this year.

"Approaching closed fans events gave us the bulk of the European season. Of course we can adjust that as we progress and we come to understand where we are with this pandemic.

"Our first half of the season is European-based. We're still pretty fluid on the second half. I think we're confident we're going to finish in Bahrain and Abu Dhabi, but we're filling in the spaces in-between."