Formula 1 driver Liam Lawson said he narrowly avoided a fatal accident during Sunday's Mexico City Grand Prix after two marshals ran across the track in front of him.

The incident happened in the third lap when marshals were seen on the circuit as Lawson rejoined the race after an early pitstop to replace a front wing.

Shortly afterwards, Racing Bulls driver Lawson said on team radio to his race engineer: "Are you kidding me? Did you just see that? I could have... killed them."

After the race, he added: "I honestly couldn't believe what I was seeing.

"[I] came out on a new set of hards [tyres], and then I got to Turn One and there were just two dudes running across the track.

"I nearly hit one of them, honestly, it was so dangerous.

"Obviously there's been a miscommunication somewhere but I've never experienced that before, and I haven't really seen that in the past. It's pretty unacceptable.

"We can't understand how on a live track marshals can be allowed to just run across the track like that. I have no idea why, I'm sure we'll get some sort of explanation, but it really can't happen again."

Formula 1's governing body, the International Automobile Federation (FIA), is investigating the circumstances.

"Following a turn one incident, race control was informed that debris was present on the track at the apex of that corner," said the FIA.

"On lap three, marshals were alerted and placed on standby to enter the track and recover the debris once all cars had passed.

"As soon as it became apparent that Lawson had pitted, the instructions to dispatch marshals were rescinded and a double yellow flag was shown in that area.

"We are still investigating what occurred after that point."