Radical Iraqi Shi'ite cleric Moqtada al-Sadr's group has accused U.S. forces of killing a senior member of the group, and has called for a government investigation.
A spokesman says U.S. and Iraqi soldiers raided the home of Sahib al-Ameri early Wednesday near the city of Najaf and shot him dead.
The U.S. military confirmed the raid, and said coalition troops killed a man who was a suspect in roadside bombing attacks.
In other violence, Iraqi police say a car bomb blast killed eight people in eastern Baghdad.
The Latvian Defense Ministry announced that a bomb explosion killed two Latvian soldiers and wounded three others in Iraq on Wednesday. They were the Baltic country's first casualties in Iraq since a Latvian soldier was killed in 2004.
The U.S. military said a Marine also died Wednesday from wounds sustained in combat in Anbar province.
In another development, the U.S. Defense Department has announced that it is sending about 3,500 troops to Kuwait to serve as a standby force for use in Iraq or elsewhere in the region. The Pentagon says Defense Secretary Robert Gates approved the move.
The troops are being sent to Kuwait as the Bush administration debates strategies for reducing the violence in Iraq and whether to send more troops there.
Some information for this report was provided by Reuters.