An American man shot dead a Pakistani motorcycle rider in a street in Lahore city on Thursday, a senior police official told AFP, claiming that he fired his pistol in self defence.

"The American national told us he was driving his vehicle and stopped at a traffic signal. He saw motorcycle riders and one pulled out a pistol. The man told us he then pulled out his pistol and fired in self-defence," Lahore police chief Aslam Tarin told AFP.

"One of the motorcycle riders died and the second was injured," he added.

"He's an American national. He's in our custody and we are investigating."

A second Pakistani man was killed a short time later when a car from the US consulate in Lahore hit two pedestrians at the scene of the shooting, Tarin added.

"One person died in the accident," Tarin said.

Television footage showed that a crowd had gathered at the scene of the incidents, setting tyres on fire in protest.

The US embassy in Islamabad could not immediately be reached for comment.