More than 1,000 stone-throwing Afghans tried to break down an outer gate at the main U.S. base here Tuesday while demanding the release of eight detained villagers. Afghan troops fired warning shots and used clubs to beat back the mob, and U.S. troops fired into the air.

It was not immediately clear whether there were any casualties in the melee. Protesters chanted "Die America!" Black smoke billowed from burning tires.

In southern Uruzgan province, officials said about 50 suspected insurgents and two Afghan soldiers died in a deadly nighttime clash, while in eastern Paktika province a candidate for parliament in Sept. 18 elections was killed by a roadside bomb, police said.

The disturbance at Bagram air base erupted when six U.S. military vehicles tried to enter the grounds. Demonstrators who were massed outside threw stones at the convoy, and soldiers in the vehicles fired into the air with handguns.

The convoy sped into the base and the mob chased after it, trying to push down a metal gate guarded by Afghan troops. Some soldiers beat the protesters with clubs, and several fired rounds from assault rifles into the air.

The eight men arrested Monday "had materials used to make improvised explosive devices in their possession and are thought to be planning future attacks against coalition forces," the U.S. military said in a statement.

Demonstrators said they were angry that U.S. soldiers arrested the men without consulting local authorities.

"We have supported the Americans for years. We should be treated with dignity," said Shah Aghar, 35. "They are arresting our people without the permission of the government. They are breaking into our houses and offending the people. We are very angry."