Fighters on Monday attacked an Iraqi army checkpoint in the al-Muradiya area west of Baquba at about 7am (0400 GMT) with machine guns and grenades, said an Iraqi soldier who was at the scene.
He did not wish to be identified.
Aljazeera learned that seven soldiers from the Iraqi National Guard were killed.
The attack also left six soldiers wounded, according to First Lieutenant Ali Hasan of the Iraqi police force.
Separately, a parked booby-trapped car in Baquba's al-Mualimin neighbourhood exploded as an Iraqi police patrol was passing by.
Iraqi police and security forces
are regularly targets of attack
First Lieutenant Mahmud Muthanna said two policemen were killed, but Aljazeera put the number at four.
The explosion at 8am (0500 GMT), also killed one civilian and wounded several others, including six policemen, according to medic Qaisar Hamid at Baquba's general hospital.
Baquba, 65km north of Baghdad has seen frequent attacks by fighters.
In Balad, a bomber blew up his car near an Iraqi army patrol on Monday, killing 15 people and wounding 18 others, Iraqi army officers at the scene said.
Balad lies on the road between Baghdad and the northern town of Samarra. Anti-US fighters have mounted frequent attacks in the area.
Meanwhile, a Jordanian businessman was seized in Iraq and his captors demanded a ransom for his release, one of his brothers said on Monday.
Anti-US fighters have mounted
frequent attacks in Balad
Ibrahim Maharma was seized on Friday in the upmarket al-Mansur neighbourhood of Baghdad "by a gang which has demanded $250,000 in ransom", his brother Bilal Maharma said.
"Yesterday morning [Sunday] we received a call from Ibrahim's office in Baghdad and one of his assistants told us that they
received a call from the kidnappers demanding the ransom," Maharma added.