[REUTERS] Insurgents attacked cities across Iraq on Monday with car bombs, suicide blasts and gun battles that killed more than 70 people in unrest that has deepened fears of a return to civil war.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.
Weeks of bloodshed have accompanied rising political tensions between Iraq's majority Shi'ite leaders and members of the Sunni community, who believe they have been marginalized since the fall of Saddam Hussein after the 2003 U.S.-led invasion.
But war in neighboring Syria, where Shi'ite Iran and the region's Sunni Gulf states are backing opposing sides, has also put pressure on Iraq's own balance among Shi'ite, Sunni and ethnic Kurds who share power in a fragile government.
Markets in two northern Iraqi towns were hit early on Monday, police said. Later attacks targeted security forces. In the northern city of Mosul, suicide bombers and rocket fire struck police headquarters, killing 24, many of them police and soldiers.