The United Nations said Wednesday that violence claimed the lives of 7,818 civilians in Iraq in 2013, the highest annual death toll in years.

Over eight months of escalated violence has sparked fears that the country may be returning to the widespread bloodshed of 2004-2007 that saw tens of thousands killed each year. Death tolls dipped following a U.S. troop surge and an alliance of Sunni militias with U.S. forces against al-Qaeda, but soaring sectarian distrust appears to be allowing the extremist network to rebuild.

Violence spiked in April after the Shiite-led government staged a deadly crackdown on a Sunni protest camp. Iraq’s al-Qaeda branch has fed on Sunni discontent and on the civil war in neighboring Syria, in which mostly Sunni rebels fight a government whose base is a Shiite offshoot sect. It has targeted civilians, particularly in Shiite areas of Baghdad, with waves of co-ordinated car bombings and other deadly attacks.