Image copyright AP Image caption Bob Renning said he has no idea how he managed to bend the door open

A man saved a driver from a burning car by bending the door with his bare hands, say police, describing his feat of "superhuman strength".

Bob Renning, 52, pulled up on a freeway in Minnesota to help another vehicle that was filling with smoke.

He told the Minneapolis Star Tribune he was not sure how he bent the door open far enough to shatter the window glass.

Police officer Zachary Hill was first to the scene and full of praise for Mr Renning's "extraordinary" heroics.

"He did an extraordinary deed, bending a locked car door in half, of a burning car, to extricate a trapped person," said Hill.

Mr Renning, a member of the US National Guard, said he sprinted towards the vehicle as he saw flames and smoke "rolling around" the SUV. His girlfriend called 911.

After he realised the vehicle was locked and the windows would not work, Mr Renning gripped the top of the door frame with his fingers, braced his foot against the door and pulled, according to the Minnesota State Patrol.

Image copyright Minnesota state patrol/Facebook Image caption The door Renning prised open bears the marks of his feat

The man in the vehicle, Michael Johannes, said he did not realise someone was trying to save him as he held his breath in the smoke-filled car.

He suffered minor smoke inhalation and light cuts from being pulled through the shattered window.

"Thirty seconds later and I would have been done," Mr Johannes said. "It was a good thing I didn't have my family in there."