The disturbances erupted Monday during a routine search of part of the inmate area at Camp Bucca prison near the border with Kuwait, a statement said.

An investigation into the riot was under way but Lieutenant Colonel Barry Johnson, a spokesman for US military prison operations, said there was "no direct" link to the country's election on Sunday.

All of the dead and injured were Iraqi, Johnson told AFP. "Some third country nationals are held at Camp Bucca but they were not involved in the disturbances."

The troubles lasted about 45 minutes before US troops opened fire, according to the military.

"The violence erupted after a routine search for contraband in one of the camp's 10 compounds," said the statement.

"The riot quickly spread to three additional compounds, with detainees throwing rocks and fashioning weapons from materials inside their living areas."