The FIA has identified the cause of the drain cover issues that have plagued the first practice session at the Las Vegas Grand Prix.
Both Carlos Sainz and Esteban Ocon suffered damage after running over drain covers, with the former stopping on track after it cut out his engine after just nine minutes of track action.
The session was red flagged and subsequently abandoned, with the FIA having to check the circuit ahead of any further on track running.
All drivers apart from Logan Sargeant completed at least one lap, with Charles Leclerc setting the quickest time.
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FIA identifies problem
An FIA spokesperson confirmed: "Following inspection, it was the concrete frame around a manhole cover that has failed.
"We now need to check all of the other manhole covers which will take some time.
"We will be discussing with the local circuit engineering team about the length of time it will take to resolve and will update with any resultant changes to the schedule."