The United Nations says at least 7,818 civilians and 1,050 members of the security forces were killed in violent attacks across Iraq in 2013.
December alone saw at least 759 people killed, 661 of them civilians.
The annual toll is the highest in five years, but still significantly below those recoded at the height of the sectarian conflict in 2006 and 2007.
Violence has surged since April, when the Shia-led government launched a crackdown on a Sunni protest camp.
Extremist Sunni militants linked to al-Qaeda subsequently stepped up attacks across the country, while Shia groups began deadly reprisals.
'Sad and terrible record'
Tensions have been raised further since Saturday, when security forces arrested a prominent Sunni MP in the western city of Ramadi, triggering clashes that left six people dead.
On Wednesday, al-Qaeda militants were said to have appeared on the streets of several towns across Anbar province, taking over abandoned police stations and army posts.
Prime Minister Nouri Maliki, a Shia, appealed to Sunni tribesmen to help combat the militants, saying he was ready to address their grievances.
Sunni Arabs have been calling for Mr Maliki's resignation for more than a year. They accuse his government of discriminating against their minority community and unfairly targeting it with tough anti-terrorism measures which officials say have been implemented to stem the violence.
Announcing the 2013 death toll, the UN head of mission in Iraq, Nickolay Mladenov, said: "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."
The Iraqi government reported that 7,154 people were killed in 2013, including security forces personnel and militants. Iraq Body Count, a UK-based organisation that has tracked violence in the country since 2003, said it had recorded 9,475 civilian deaths.
"If current violence levels continue unabated throughout the coming year, then 2014 threatens to be as deadly as 2004, which saw the two sieges of Fallujah [by US forces] and Iraq's insurgency take hold," IBC said.