The explosion happened during the afternoon in the town of Baladruz in Diyala province, China's Xinhua News Agency reported.
"Five policemen and two civilians were killed, while 17 civilians and five policemen were wounded by the blast," a provincial police official told Xinhua.
The blast also damaged a police vehicle and several nearby civilian cars, the official said.
Earlier Monday, four people were killed, including a police officer, and seven people wounded in three bomb attacks near Baghdad, police said.
Notable deaths of 2014 [PHOTOS]