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.

More than 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-Qaida, 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-Qaida 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. The branch has targeted civilians, particularly in Shiite areas of Baghdad, with waves of co-ordinated car bombings and other deadly attacks.

The U.N. figures gave a total of 759 people killed in December alone, including 661 civilians and 98 members of the security forces. Another 1,345 were wounded, the statement said. The U.N.’s monthly figures for both civilians and security forces over the year totaled 8,868.

Mission chief Nickolay Mladenov called on Iraqis to take the necessary steps to stem violence. “This is a sad and terrible record which confirms once again the urgent need for the Iraqi authorities to address the roots of violence to curb this infernal circle,” Mladenov was quoted in the statement as saying.

The insurgency appears to have capitalized on a protest movement by Sunnis angered at what they consider second-class treatment, and the government’s crackdown on it.

On Wednesday, al-Qaida gunmen fanned out in the streets of towns in the volatile western province of Anbar amid Sunni anger over the arrest of a prominent Sunni lawmaker and the dismantlement of a year-long sit-in the provincial capital of Ramadi in recent days.

A provincial spokesman said al-Qaida fighters brandished their weapons in the streets of Ramadi and other towns, taking over police stations and military posts after security forces left. Dhari al-Rishawi said that in the former insurgent stronghold of Fallujah, gunmen broke into the main police station, setting free dozens of inmates and taking weapons.

Iraq’s Shiite prime minister, Nouri al-Maliki, appealed to Sunni tribes to team up with security forces to fight the militants, expressing his government’s readiness to listen to Anbar residents to address their needs.

“I call upon on all generous tribes in Anbar to adopt a courageous stance … and other tribes in (the provinces of) Diyala, Salaheddin, Ninevah, Baghdad and other parts of Iraq to come together,” al-Maliki said.

“I say that all our brothers in Anbar are welcomed for discussion or negotiations,” he said. “We want them to come here (in Baghdad) so that we can put our hands together for the sake of Anbar to protect it from foreign agendas and Takfiri ideology.” Takfirism refers to hard-liners who consider other Muslims to be infidels, and Maliki’s invocation of it appears to be an attempt to remind Sunnis in Anbar, who were among the first to turn on al-Qaida in 2005-2007, that they too had been targeted by extremists.