Formula 1's race director Niels Wittich has left his role immediately, the FIA said on Tuesday, in a surprise move.
The German, who replaced Michael Masi in 2022, will be replaced for the Las Vegas Grand Prix on November 23 by Rui Marques, who was recently the race director for Formula 2 and 3.
"The FIA can confirm that Niels Wittich has stepped down from his position as F1 Race Director to pursue new opportunities," the FIA said in a statement.
It is extremely rare for an F1 race director to be changed mid-season, but the FIA did not elaborate on the reasons for his departure.
Masi was removed as Formula One race director after his controversial management of the season-ending 2021 Abu Dhabi Grand Prix where Max Verstappen pipped Lewis Hamilton to the title.
It is not clear if Wittich is the latest victim of a disagreement with FIA president Mohammed Ben Sulayem.
A number of staff in senior FIA roles have resigned this year.