US and Iraqi troops clashed with the fighters on Saturday near the northern city of Tal Afar.
Six policemen died when armed men attacked a checkpoint in Baquba, 55km northeast of Baghdad, according to Dr Ahmed Fouad, chief of the local morgue.
Three Iraqi soldiers were also killed on Saturday when their convoy was attacked near Adhaim, 50km north of Baquba, according to police Colonel Abd Allah Qadir.
Elsewhere, Iraqi civilians reported fighting late on Friday in the outskirts of Tal Afar, an ethnically mixed fighter stronghold 420km northwest of Baghdad.
Hospital officials said they were unsure about casualties because it was too dangerous for ambulances to reach the area.
US armoured vehicles could be seen in the hills outside the city, the Iraqis said.
Iraqi police clashed with fighters late on Friday at the Tal Afar bus station after receiving reports that fighters were storing weapons there, Iraqi Brigadier-General Said Ahmad al-Jiburi said.
One fighter was killed and six others were arrested.
In Samarra, 95km north of Baghdad, four civilians were killed and 11 injured when three mortar shells fired at a US installation missed the target and landed in a residential area, police said.
Oil pipeline fire
Also on Saturday, a major Iraqi crude oil pipeline was hit by an explosion and caught fire for several hours, said a guard who declined to be identified.
Oil pipelines have come under
The pipeline runs from the major northern Iraqi oilfield of Kirkuk to the Turkish Mediterranean port of Ceyhan. The explosion took place near Fatha, between Kirkuk and the city of Baiji.
Another guard said a roadside bomb had been placed beside the pipeline some 4km from Fatha, which is 95km southwest of Kirkuk.
By 2.30pm the fire had been extinguished, a fire department official from Iraq‘s North Oil Company said. But he added that oil leaking from the pipeline had spilled some 2km from the site of the explosion.
It was not immediately clear how long it would take to repair the line and bring it back to full capacity.
The US-based Congressional Research Service, in an April 2005 report, said the Kirkuk-Ceyhan pipeline consisted of two parallel pipes.
One has a practical capacity of 900,000 barrels per day while the other has a capacity of 500,000 bpd.