Formula 1 is "assessing the situation" as it emerges that Turkey may have to be scrapped from the 2021 calendar.
The circuit in Istanbul was only added to the schedule recently, after Canada's Montreal race was cancelled for the second consecutive season due to covid.
But now a similar situation is evolving in Turkey, with the UK government deciding to add the country to its covid-19 'red list'.
British transport secretary Grant Shapps says Turkey should now "not be visited except in the most extreme of circumstances".
It is a major problem for Formula 1, as many of the teams are based in England and returning UK citizens must quarantine upon their return from Turkey for 10 days - at a per-person expense of about $2500.
"We are aware of the statement made by the UK government regarding travel restrictions to Turkey," a Formula 1 spokesperson told international publications.
"We are assessing the situation and will provide more information in the coming days."
It is rumoured that the Nurburgring or Mugello are the most likely replacement hosts in the event that Turkey is scratched.