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BAGHDAD, June 9 (Reuters) - Six civilian detainees were killed and at least 50 wounded when rockets or mortars were fired into the U.S.-run Camp Bucca prison in southern Iraq on Saturday, the U.S. military said.

Military spokesman Lieutenant-Colonel Christopher Garver said the attack involved an unspecified number of mortar rounds or rockets fired into the prison. He gave no further details.

U.S.-run detention camps, such as the former Abu Ghraib prison in western Baghdad, have been attacked by insurgents in the past, but such attacks are rare.

About 16,000 detainees are held in Camp Bucca and Camp Cropper near Baghdad.

Sunni Arabs, dominant under Saddam Hussein and who make up the backbone of Iraq's insurgency, account for the vast majority of detainees in U.S.-run prisons in Iraq.

Iraq took over control of Abu Ghraib, notorious for a prisoner abuse scandal involving U.S. troops, last September.

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