Formula One race directors Eduardo Freitas and Niels Wittich have both tested positive for COVID-19, raising questions about who will take charge of next week's inaugural Miami Grand Prix, British media reported on Wednesday.
A well-placed source confirmed to Reuters that the news, first reported by the Daily Telegraph and Sky Sports television, was correct.
A spokesman for the governing FIA said medical information about its personnel could not be disclosed "unless it is relevant to the running of an event".
Sky said it understood both men had tested positive after last weekend's Emilia Romagna Grand Prix at Italy's Imola circuit.
Travel to the United States currently requires a negative test taken no more than a day before departure, regardless of vaccination status.
Practice for the May 8 race starts on May 6, which is next Friday.
Portuguese Freitas and German Wittich were appointed in February as alternating replacements for now-departed Australian Michael Masi after a review of last year's controversial season-ending race in Abu Dhabi.
Masi changed safety car procedures late in the race, a decision that effectively handed the title to Red Bull's Max Verstappen.
Should neither race director be available for the race at the Hard Rock Stadium, other options could be British veterans Herbie Blash and Colin Haywood.
Formula E race director Scot Elkins would be another candidate and would be available to work next weekend.