British troops and Iraqi police have clashed with stone-throwing and armed protesters in the southern Iraqi city of Amara, killing at least five people.

British military officials say hundreds of Iraqis angry at the lack of jobs in Amara gathered outside the local government headquarters. They say Iraqi police opened fire after demonstrators began throwing stones at the building.

British troops were called in to help restore order. British officials say troops shot and killed one man who was throwing a grenade. Explosive devices were also thrown at British military vehicles on the scene.

Iraqi medical personnel put the death toll at six and say several other Iraqis were wounded in the clash.

Meanwhile, Danish soldiers in southern Iraq uncovered three dozen mortar shells Friday leaking an unknown fluid and sent them for testing for chemical agents. A U.S. military official says the shells wrapped in plastic bags and buried in the desert near the city of Basra.

In other developments, U.S. Brigadier General Mark Kimmitt said Saturday that a preliminary investigation into the crash of a U.S. Army medical evacuation helicopter in Iraq on Thursday indicates it was probably shot down. The Black Hawk crashed near the flashpoint town of Fallujah, killing all nine soldiers on board.

Iraqi witnesses had reported seeing the Black Hawk on fire before it crashed. Others said the helicopter was hit by a rocket. Fallujah has been a hotbed of insurgent activity, and another U.S. military helicopter crashed there the week before.