McLaren boss Zak Brown has warned Formula One could lose up to eight cars from the grid if the coronavirus crisis continues to disrupt the schedule.
Brown said the sport is in "a very fragile state" with the season start put back to at least June. Last month's opener in Australia was initially postponed and has now been cancelled, while the showcase race in Monaco has also been pulled from the schedule.
Six other races remain hopeful of finding a new slot in the calendar, and the axe now looms for June's Canadian Grand Prix.
British Grand Prix organisers have been told they must make a decision about July's race by the end of April.
The sport has already responded to the pandemic by postponing a planned major technical rule change from 2021 to 2022, and it has been agreed that teams will use the same cars next year but Brown said more was needed.
"Could I see - through what is going on right now in the world if we don't tackle this situation head on very aggressively - two teams disappearing? Yeah," the American told the BBC.
"In fact, I could see four teams disappearing if this isn't handled the right way."
Brown said the economic and health situation meant it should not be assumed anyone would be lining up to take over any struggling teams.
"I don't think the timing could be worse from that standpoint," he added. "So I think F1 is in a very fragile state at the moment."
