Lewis Hamilton has been summoned by the stewards in Mexico for failing to follow the race director's instruction.
The summons relates to Michael Masi's instruction that any driver who leaves the track on the left-hand side between Turns 1 and 2, or who passes to the left of the bollard on the apex of Turn 2, must re-join the track by driving to the left-hand side of the bollard at Turn 3.
Early in the session, the world champion, having gone off at Turn 1, rejoined the track before driving to the left of the bollard at Turn 3, as did Kimi Raikkonen shortly after.
Consequently both drivers have been instructed to meet the stewards before FP2, at which point both are expected to receive reprimands.
A very dusty track saw a number of drivers go off at various points on the track, Charles Leclerc and Sergio Perez both incurring damage after clouting the barriers at Turn 16 in the stadium section.
Hamilton finished the morning second quickest, just 0.076s down on his Mercedes teammate, Valtteri Bottas.
Check out our Friday gallery from Mexico City, here.