Pakistan, May 19 -- Alex Marquez and Johann Zarco will remain in hospital after the two riders sustained fractures in separate crashes that forced the Catalan Grand Prix to be red-flagged twice on Sunday.

Gresini Racing's Marquez could not react in time when Pedro Acosta's bike lost power and he slammed into the back of the KTM, before he careered towards the wall and then cartwheeled through the air as he lost control on the gravel.

Marquez was immediately rushed to the hospital where scans confirmed he had a marginal fracture on the vertebra near his neck as well as a fracture on his right collarbone, with the Spaniard set to undergo surgery later on Sunday.

"Everything's under control. I'm due to go into the operating theatre tonigh...