The four soldiers and their Iraqi interpreter were killed when the bomb detonated near the patrol on Wednesday in the eastern half of the Iraqi capital during "combat operations", the military said.

It did not specify the exact location of the blast.

Another service member, a Task Force Marne soldier, was killed by small arms fire on Thursday south of Baghdad, the military said in a separate statement.

Meanwhile, Sunni lawmakers ended their five-week boycott of parliament Thursday, raising hopes the factious assembly can make progress on benchmark legislation demanded by Washington. The US announced that two American soldiers have been charged with killing an Iraqi.