Six people died on Wednesday during clashes between US troops and armed men in the northern city of Mosul.
A car chased by US military vehicles was headed towards a US-Iraqi checkpoint in Mosul when a firefight broke out, said a witness.
"The car caught fire and the four suspected insurgents inside were burnt to death, while a woman and a child bystander also were struck down," said policeman Naqib Isam Abd al-Wahid.
Another three men and women were wounded during the fight, he said.
Soldiers, policeman killed
An hour-and-half later, armed men in the central al-Rifia district of Mosul shot dead police Captain Ibrahim Amir outside his home and tossed a grenade at him.
US troops are struggling to
restore law and order in Iraq
"There were several people in the car who opened fire on his home. They threw grenades before leaving," said policeman Sami Samir al-Jaburi.
Aljazeera has learned that eight Iraqi soldiers were killed and three others injured in a car bomb attack that targeted their patrol in Somar neighbourhood, southeast of Mosul.
Another two bodies, apparently executed with shots to the chest and head, were delivered to Mosul's Medical City hospital in the morning, a doctor there said.
In other violence around Iraq, nine people died on Wednesday.
In Abu Ghraib, west of Baghdad, a school guard died in a car bombing and a school teacher was wounded, an interior ministry official said.
North of Baghdad, two men died when a bomb they had prepared blew up prematurely by a water pumping station in Khalis, about 80km from Baghdad, an army colonel said.
Car bombs have become a nearly
daily part of Iraqi life
In Balad, 70km north of Baghdad, an armed fighter was killed and an Iraqi soldier was wounded during an hour-long shootout, while in nearby Dujail, unknown men kidnapped a truck driver and killed his passenger, security officials said.
Close to Baiji, 200km north of the capital, two brothers who worked for the Iraqi army were found dead by soldiers, said an army captain.
An Iraqi army soldier died in al-Sedira, 300km north of Baghdad, when a mortar struck his post, said Samarra police Captain Nawar Saad.
The US marine killed during the day was assigned to the 2nd Force Service Support Group. The military said he was en route to Qaim, a city near the Syrian border in western Iraq, when his vehicle hit a landmine.
A US drone also crashed during the day in al-Anbar province west of Baghdad, the US military said without specifying what brought it down.
"An Air Force MQ-1 Predator unmanned aerial vehicle crashed in Rawah, Iraq," said a statement.
"A board of officers will investigate the accident."
The British army has apologised
for raiding an Iraqi MP's home
Meanwhile, a Mississippi Army National Guard soldier lost his legs and three other soldiers were also injured when their vehicle hit an improvised explosive device in Iraq, Guard officials and the soldiers' families said on Wednesday.
The men are members of the 155th Brigade Combat Team.
Meanwhile, the British army apologised for barging into the home of an Iraqi MP in the southern city of Basra and arresting his relatives.
"It has subsequently become clear that the information that we acted on was wrong. We unreservedly accept that the individuals detained are innocent and they have now all been released," the military said in a statement.
A deputy from Basra, Mansur al-Tamimi, lashed out during Tuesday's Iraqi parliament session at British troops for blasting into his home in the southern city overnight and arresting 12 members of his family, who were later released.