The U.S. military says four American soldiers have been killed in an explosion during fighting south of the Iraqi capital of Baghdad.
A statement Sunday said the soldiers were killed and another four were wounded in the blast during combat operations on Saturday.
In another incident, the military said a soldier was killed by small arms fire Saturday while on foot patrol southeast of Baghdad.
Also Saturday, a roadside bomb killed the governor and police chief of Diwaniyah province, a Shi'ite area, south of Baghdad.
Medical workers said three members of the governor's security detail also died along with Governor Khalil Jalil Hamza and the police chief, Khalid Hassan. The powerful bomb exploded as a convoy of vehicles drove past, returning to Diwaniyah, the provincial capital from a nearby town where officials had attended a tribal sheikh's funeral.
Authorities imposed a curfew on Diwaniyah province following the attack.
The Diwaniyah region has seen a rise in internal rivalries among Shi'ite militias, and U.S.-led security forces in the area have been the target of frequent attacks.
Meanwhile, U.S. Attorney General Alberto Gonzales arrived in Baghdad Saturday on a visit to meet with members of his Justice Department who are in Iraq working to rebuild the country's legal system.