Jeremy Renner was injured by snowplough when trying to save nephew

Actor Jeremy Renner was trying to stop a snowplough from crashing into his nephew when he became trapped and it crushed him, a police report discloses.

The Marvel star was using the six-tonne PistenBully plough to help Alexander Fries free his car from the snow.

But the large vehicle then began to roll down the hill, a Washoe county sheriff's department report said.

Renner sustained injuries to his "torso, face, extremities and head" during the accident.

The actor, known for playing bow-wielding Marvel superhero Hawkeye, has been recovering in hospital since.

Renner previously said he had broken more than 30 bones in the incident, but they would "grow stronger, just like the love and bond with family and friends deepens".

The accident occurred around the new year, near the Mount Rose Highway, which links Lake Tahoe and south Reno as it straddles the Nevada-California border in the US.

A report by deputy Garret Leone, obtained by the Press Association, said that after Renner had arrived at the scene, he had spoken to his nephew - who had been the only one present.

"Jeremy is his uncle and was helping him get the Ford pickup truck out of the driveway. The pickup truck got stuck multiple times, so they used the PistenBully to pull the truck out of the driveway," Deputy Leone's report said.

"They had a chain connected to the back of the PistenBully and to the front of the Ford pickup. They got the pickup truck out of the driveway and Alexander parked in the middle of the street.

"Jeremy turned the PistenBully around further west on Drive. Once turned around, Jeremy exited the PistenBully in an attempt to speak to Alexander.

"Alexander observed the PistenBully traveling eastbound on Drive directly towards him with nobody inside driving the vehicle.

"While running towards the truck, Alexander observed Jeremy jumping on the tracks of the PistenBully to get in the cab of the vehicle. Alexander said Jeremy got caught on the PistenBully trucks and was ultimately run over by the PistenBully."

Mr Fries had begun "screaming for help" as he did not have his phone, and was assisted by two neighbours who provided towels and assistance to Renner while medical personnel arrived.

Another report from deputy Jonathan Miller added that "in an attempt to keep the PistenBully from striking his nephew, [Renner] attempted to step up on the track in order to divert the PistenBully or get it stopped.

"Renner was pulled under the PistenBully, and the track rolled over him," the report said.

The actor has kept fans updated with his recovery process since the accident. On Saturday, he thanked those who sent him messages of support.

As Hawkeye, Renner has appeared in Marvel films including Thor, Black Widow, Captain America: Civil War and Avengers: Endgame, as well as the character's eponymous TV series.

His other film credits include The Hurt Locker, Arrival, 28 Weeks Later, American Hustle and Mission: Impossible - Ghost Protocol.

Renner also starred in 2012's The Bourne Legacy - the only film of that franchise not to feature Matt Damon in the lead role - and recently made a cameo appearance in Knives Out sequel Glass Onion.