Four American troops were killed in a roadside bombing, as gunmen tried to kill a leading Shiite politician in a separate attack on Tuesday, the last day of campaigning for Iraq's election.
The bombing northwest of Baghdad killed four US soldiers which belonged to a unit handling security in the capital and the surrounding area.
Elsewhere, a roadside bomb targeted the convoy of Sheikh Jalal Eddin al-Sagheer, a Shiite member of the National Assembly who was elected with the governing United Iraqi Alliance. The Iraqi army said the blast in Latifiyah, about 20 miles south of Baghdad, damaged one of the vehicles.
In another incident, police said a roadside bomb intended for one of their patrols in the central city of Samarra missed, instead killing a child and seriously wounding his father.
Meanwhile, over 1,000 Sunni clerics, published a religious edict (fatwa), calling their followers to vote in Thursday's balloting.
On his part, Ali al-Lami, executive director of the Iraqi Electoral Commission, called for peace when about 15 million people will be called on to vote in more than 6,200 polling stations.