Guerrillas armed with AK-47s and rocket-propelled grenades have attacked a police station in Baghdad, killing at least three policemen.
The fighting came a day after Iraqi troops backed by US soldiers raided a major mosque in the Aadhamiya of the Iraqi capital and clashed with worshippers.
At least four people were killed in the clashes at the Abu Hanifa mosque, and nine wounded.
In western Baghdad, a roadside bomb exploded as an Iraqi National Guard convoy drove past, destroying one vehicle.
Elsewhere in Baghdad, insurgents ambushed a US patrol in a co-ordinated attack using roadside bombs, assault rifles and rocket-propelled grenades, killing one soldier and wounding nine.
Since the US-led invasion in March last year, at least 947 American military personnel have been killed in action in Iraq.
Separately, a US military spokesman has said the identities of four headless corpses found in the northern city of Mosul remain unclear.
Another US officer in Mosul said the bodies were thought to be those of policemen killed by insurgents.
Red Cross critical of all sides in Iraq war
The International Committee of the Red Cross has issued a strong statement criticising what it calls the utter contempt for humanity shown by all sides in the fighting in Iraq.
The Red Cross referred to the shooting of a wounded fighter by US forces in the city of Fallujah and the killing of Margaret Hassan.
It said killing those not taking an active part in fighting and taking hostages were prohibited under international humanitarian law.
More US troops may be sent to Iraq
The US military has announced plans to send more troops to Iraq before elections in January.
Lieutenant General Lance Smith said military commanders are considering whether or not to boost troops levels in Iraq by several thousand as the elections approach.
However, he said the final decision would depend in part on whether the insurgency strengthened or weakened after the offensive in Fallujah.
