Police said a total of six explosions were caused by roadside bombs planted near houses belonging to security officers in Baqouba as their families were sleeping. Two children died in the blasts and nine people were wounded.
The city, 60 km northeast of Baghdad, is a former stronghold of Al-Qaeda militants.
Meanwhile, police said gunmen stormed the house of a leader in the anti-Al-Qaeda militia, killing him and his wife in the predominantly Sunni suburb of Abu Ghraib, west of the capital.
The man had been active in the Sahwa, or Sons of Iraq, a Sunni militia that was instrumental in turning the tide against Al-Qaeda in the country.
The latest violence comes amid a growing political crisis that erupted after Prime Minister Nuri Al-Maliki's government issued an arrest warrant for the country's top Sunni politician last month.
Al-Maliki's main political rivals, the Sunni-backed Iraqiya bloc, is boycotting Parliament sessions and Cabinet meetings in protest over what they say are efforts by the Shiite-led government to consolidate power and marginalize them.
