Plans to allow up to 100,000 fans to attend the return of the Turkish GP in November have been shelved by local officials after a rise in coronavirus cases.
The event at Istanbul Park on November 13-15 will now run behind closed doors, confirmed Istanbul Governor's office on Monday. The race is returning to the calendar for the first time in nine years.
An F1 spokesperson said: "Our season has been guided by a safety first approach and that will continue to be our priority.
"In Turkey we were looking forward to seeing fans but the situation in the country means this is no longer possible and we fully understand and respect the decision."
A limited number of spectators have been allowed back at the last two F1 events, at Italy's Mugello and Russia's Sochi Autodrom.
Almost 3,000 were allowed to attend each day at Mugello, while Sochi was open to around 30,000 people per day.
A crowd of up to 20,000 is set to attend this week's Eifel GP at the Nurburgring, while some fans are also expected at the following two European events in Portugal and Imola.
In the most recent round of F1 coronavirus test results published last Friday, the sport made clear that the presence of fans at the Russian GP was not linked to a small rise in positive cases.
Of the 1,822 COVID-19 tests carried out between September 25 and October 1, 10 people tested positive. The positive cases were among ancillary personnel and not those involved in race operations.
"Those cases and have been managed quickly and effectively without impacting the event," said an F1 statement. "The presence of fans has not affected that situation as the public was not allowed to enter the F1 bubble as per our protocol in force."