At least US soldiers have been killed in Iraq including four in a single incident, the US military has said.

A roadside bomb killed four soldiers on Saturday while they were on patrol in western Baghdad, the military said in a statement on Sunday.

Small arms fire followed the blast, wounding another soldier.

The attack occurred as the soldiers were conducting patrols as part of a month-old security operation to end sectarian violence in the capital, the statement said.

Another soldier died the same day in a non-combat related incident, the military said.

The deaths raise to at least 3,215 the number of US troops who have died since the Iraq war started in March 2003, according to a count by the Associated Press news agency.

Other attacks

Armed groups also killed three people, including a policeman, in two separate incidents early on Sunday in Baghdad despite a massive security crackdown in the Iraqi capital.

Security officials said a policeman and a civilian were killed and five policemen wounded when a roadside bomb struck a police patrol near the renowned Al-Mustansiriyah University in east Baghdad.

Another civilian was killed and one wounded in a mortar attack in central Baghdad's Al-Fadhel district, another security official said.

Armed groups have managed to carry out attacks in Baghdad despite the presence of 90,000 US and Iraqi troops on the city's streets as part of Operation Fardh al-Qanoon [Imposing Law]  launched to curb the violence.

PHOTO CAPTION

An U.S. Marine Cpl. of the group Iraq Veterans Against the War stands near a flag-draped casket decorated with the boots, dog tags and a photo of a fellow Marine who was killed in the war in Iraq, as protesters against the war in Iraq gather for the March on the Pentagon in Washington, March 17, 2007. (REUTERS)