No group claimed responsibility for the day-long attacks, most of them in northern Iraq, but officials blame much of the violence that has killed nearly 2,000 people since April on Sunni Islamist insurgents linked to al Qaeda's local wing.
The bloodshed has accompanied rising political tensions between Iraq's majority Shi'ite leaders and the Sunni community, who believe they have been marginalized since the fall of Saddam Hussein after the 2003 U.S.-led invasion.
The recent monthly death tolls have been the worst since inter-communal bloodletting five years ago that killed tens of thousands, partitioned Baghdad into districts based on religious sect and drove Iraq to the edge of wide scale civil war.
The increasingly sectarian conflict in neighboring Syria, where Shi'ite Iran and the region's Sunni Gulf powers are backing opposing sides, has also put pressure on Iraq's own fragile inter-communal and ethnic balance.
Invigorated by Syria's mostly Sunni revolt and Iraqi Sunni discontent, al Qaeda's local wing, Islamic State of Iraq, is recruiting and regaining ground lost during its war with U.S. troops who left Iraq in December 2011.