A medical source at the hospital in Mahmudiyah said it had received the bodies of eight members of a Shiite family -- a man, a woman and six children aged between four and 14 years old. All had been shot in the head.
Gunmen also attacked a house in Saadiyah near Khanaqin, 150 kilometers (95 miles) northeast of Baghdad, martyring Mohsen Hassan, an Iraqi communist party member, and his wife, Shahad Ahmed, a police lieutenant colonel and a Baquba hospital doctor said.
The Iraqi communist party was once of one the strongest in the region but was decimated by now-executed dictator Saddam Hussein.
The shootings come just two days after a wave of bomb and gun attacks martyred 80 people and wounded more than 300 across Iraq, the country's deadliest day in almost 10 months.