An interior ministry source said that a car bomb went off near a court in western Baghdad on Monday, killing at least five people and wounding 10.
Police said that an earlier car bomb exploded near a police patrol on Palestine Street in the east of the capital killing two policemen and wounding 12 Iraqis.
Two more policemen and the driver of a bus carrying government employees to work in Baghdad on Monday were shot dead in a separate incident.
Also on Monday, the US command reported one American soldier had been killed and another wounded in northern Iraq.
A spokesman said the soldier died on Sunday near Tal Afar while US troops were with Iraqi forces attacking a building where armed men were believed to be firing at civilians and soldiers.
A US soldier secures the scene
of a car bomb attack in Baghdad
One American was also wounded in the Tal Afar clash.
The fatality raised to at least 2,420 the number of US military personnel who have died since the start of the war in March 2003, according to an Associated Press count.
Fighters bombed an oil pipeline south of Baghdad on Sunday night.
The Musayyib power station, which is supplied with oil from the Dora refinery via the line, was closed after the attack.
In other developments on Monday, police found the bodies of seven men who had been kidnapped and executed, apparently the latest victims of sectarian death squads in Baghdad.
The bodies of two Iraqi journalists working for local television channel Al-Nahrain TV were also recovered after the men were shot dead on Sunday south of Baghdad by assailants dressed in police uniforms, their station manager said.
Four civilians were hurt when a roadside bomb aimed at a US convoy in southeastern Baghdad went off. The blast damaged one American vehicle but no US casualties were reported.
Another roadside bomb exploded near a US convoy on a road between Najaf and Karbala, with witnesses reporting casualties.
Police Captain Muhammad Abd al-Ghani said a parked car bomb meant for an Iraqi police patrol in eastern Baghdad, wounded two civilians and a policeman.
In London, Britain released the names of five military personnel missing and presumed dead in a Basra helicopter crash that prompted violent demonstrations at the weekend.
British soldiers loading the body
of a comrade into an ambulance
Britain's defence ministry said those believed killed in the crash were Wing Commander John Coxen and Flight Lieutenant Sarah Mulvihill of the Royal Air Force; Lieutenant Commander Darren Chapman and Lieutenant David Dobson of the Royal Navy and Marine Paul Collins.
The crash brings the number of British service personnel who have died in Iraq to 109. About 8000 British soldiers are in the country, mainly in the south.