The US military said a marine was killed "in enemy action" in the western province of Anbar on Friday, bringing the number of US military dead since the March 2003 invasion to 2,465.
In Baquba, armed men on Saturday shot at the convoy of Kahtan al-Bawi, chief office administrator for the police and brother of city chief of police Gassan al-Bawi, killing him and two other officers.
Five workers were killed when anti-government fighters opened fire on their car workshop in Baquba, north of Baghdad, according to police.
Nearby, assailants killed a former Baath-era police officer and a relative as they travelled in their car while three police officers were wounded in a roadside bombing west of the city.
Hadi Abdul Mohsim, director of the Baquba branch of the Iraqi Association for the Defence of Human Rights, was wounded in an attack on his vehicle north of the city.
In Baghdad, one police officer was killed and another wounded when a bomb was set off against their patrol in the upscale Mansur district, an interior ministry source said.
Another two police officers were shot dead in separate incidents in Tikrit, the hometown of former Iraqi president Saddam Hussein, and another in Kirkuk.
In Samarra, a merchant in the city's central Bazaar was killed by armed men, and in the Abu Ghraib area west of Baghdad four people were hurt when a roadside bomb exploded.