KABUL (AP) - More than 250 Afghans were arrested after a riot last week in Kabul that killed about 20 people and wounded more than 120, the intelligence chief said Wednesday.

Amrullah Saleh said 141 Afghans remain in custody and 52 have confessed to crimes committed during the May 29 riot, which were sparked by a deadly crash involving a U.S. military vehicle.

Meanwhile, a U.S. military spokesman, Col. Tom Collins, said an Afghan investigator will have full access to U.S. soldiers and equipment during the inquiry into the crash. U.S. soldiers from the convoy involved will be made available for interviews, he said.

Collins told a news conference that although more than 2.5 million people live in Kabul, only about 1,000 people took part in the riot. Saleh, speaking at a separate news conference, said some people were forced to participate by small gangs wielding guns.

Saleh said he could not yet say if a specific group - one opposed to the government of President Hamid Karzai, for instance - was behind the riot. He did say Afghan authorities had identified 10 people who led or encouraged the demonstrators.

The crash, which killed up to five people and involved several cars, was caused by a U.S. military truck whose brakes failed, the U.S. military has said.

At first the demonstration was confined to a few dozen people throwing rocks at U.S. troops, but it soon ballooned into a full-fledged riot that included indiscriminate gunfire, looting and attacks on foreign houses and aid groups.

Saleh said fewer than 20 people were killed in the riots - although he did not give an exact number - and 122 were wounded. Other tallies have put the number of deaths at around 20.

The Afghan parliament has passed a non-binding resolution calling for the U.S. troops involved in the crash to be prosecuted in Afghanistan, but U.S. officials say the United States and Afghanistan have an agreement that excludes U.S. soldiers from being prosecuted locally.

Afghans on the scene of the accident have accused U.S. troops of firing into the rock-throwing crowd. The U.S. military has said only that there were indications a soldier may have fired above the crowd. AP Television News video appeared to show a machine-gun on a Humvee military vehicle firing above the crowd but not into it.