Afghanistan's parliament has approved a motion calling for the government to prosecute the U.S. soldiers responsible for a deadly road crash that sparked the worst riot in Kabul in years, officials said Wednesday.

The assembly passed the nonbinding motion Tuesday, after debating Monday's crash in which a U.S. truck plowed into a line of cars, killing up to five Afghans and sparking citywide, anti-foreigner riots, said Saleh Mohammed Saljuqi, an assistant to the parliamentary speaker.

"Those responsible for the accident on Monday should be handed over to Afghan legal authorities," Saljuqi cited the motion as saying.

A U.S. military spokeswoman, Lt. Tamara D. Lawrence, said she had not seen the motion and declined to comment.

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Hours earlier, a military spokesman, Col. Tom Collins, told a press conference that the driver of the truck was not suspected of any wrongdoing and had not been arrested. He said the truck's brakes are believed to have overheated and failed.

A spokesman for President Hamid Karzai, Khaleeq Ahmed, declined to comment on the matter.

Speaking to reporters, Collins also said that he had been informed by the Afghan Ministry of Health that the toll from the unrest had risen to 20 dead, with more than 160 wounded.

A spokesman for the ministry, Abdullah Fahim, said the final toll was still being counted. Hospital officials say most of the dead and wounded were shot.

Collins said the military was investigating whether the troops involved in the crash fired their guns into a group of violent demonstrators or over their heads.

He said some of the rioters who were throwing stones at the U.S. troops also had weapons and were firing at them.

"Our soldiers used their weapons to defend themselves," he told reporters in Kabul.

Asked if this meant that they fired into or over the crowd, Collins said, "Our investigation is still looking into this."

Though no U.S. soldiers were hurt in the riot, the spokesman said this did not mean they were not in danger.

"Deadly intent on the part of the aggressors can be a rock caving in the side of your head. Our soldiers felt threatened," he said.

Rioters stoned the U.S. convoy, then headed to the city center, ransacking offices of international aid groups and searching for foreigners while chanting "Death to America!" It was the deadliest unrest in Kabul since the fall of the Taliban in 2001, and hundreds of armed Afghan security forces were deployed to contain it.