California police warn against doing stunts at Paul Walker crash site

Police in the US city where Fast and Furious star Paul Walker died warned fans against "burning rubber" near the spot where he was killed, as they probed the fatal car crash.

They issued the caution on Monday after reports of people pulling stunt manoeuvres on the stretch of road in Santa Clarita, northwest of Los Angeles, where Walker died in a fiery smash on Saturday.

A makeshift shrine has sprung up at the place where Walker was killed when the red Porsche sports car in which he was a passenger slammed into a tree and caught fire.

Speed is believed to have been a factor in the accident, although investigators are also probing the burned-out wreckage for evidence of any mechanical problems. They appeared to discount suggestions the vehicle was involved in a drag race.

Accident investigators "have received eyewitness statements that the car involved was travelling alone at a high rate of speed", the Los Angeles County Sheriff's Department said in a written statement. "No eyewitness has contacted the (department) to say there was a second vehicle."

Some fans of the blockbuster franchise have apparently been paying tribute by pulling hot-rod stunts on the four-lane highway where the accident occurred.