A look at the deadliest attacks in Iraq since the withdrawal of U.S. troops on Dec. 18, 2011:

— Sept. 9: Insurgents kill at least 82 people in a wave of attacks, gunning down soldiers at an army post and bombing police recruits waiting in line to apply for jobs.

— Aug. 16: A blistering string of bombings and shootings across the country kill at least 93 people and wounded many more in a deadly show of force aimed at undermining the government's authority.

— July 23: Attacks aimed largely at security forces kill 115 people in what was the country's deadliest single day in two years.

— July 3: Bombs pound six cities and towns, killing some 40 people and raising suspicion that security forces may be assisting attacks on Shiite Muslims.

— June 28: Bombings and shootings take the lives of 22 people in attacks in Shiite neighborhoods and on security forces.

— June 16: Two car bombs kill at least 26 people in the capital on the final day of the Shiite pilgrimage.

— June 13: Car bombs strike Shiite pilgrims in several cities, killing 72 people in 16 separate explosions targeting an annual pilgrimage.

— June 4: A suicide bomber detonates an explosives-rigged car outside Iraq's main religious affairs office for Shiite Muslims, shearing off the facade of the three-story building and killing at least 23 people.

— April 19: Bombs rip through 10 Iraqi cities, killing at least 30 people and shattering a month of relative calm. Al-Qaida later says the attacks aimed to punish the Shiite-led government and its allies.

— March 20: Insurgents bent on derailing an Arab League meeting in Baghdad kill 46 in attacks on Shiite pilgrims in the holy city of Karbala, firebombings in Kirkuk, and strikes on security and government officials around the country.

— March 5: Assailants waving al-Qaida's battle flag gun down 25 policemen in a brazen, well-orchestrated attack in Haditha, challenging government control over the strategic town.

— Feb. 23: Attackers kill at least 55 people as car bombs go off near an elementary school in the town of Musayyib, a restaurant in a Shiite neighborhood in Baghdad, and various checkpoints and secure areas.

— Feb. 19: A suicide bomber detonates his car as a group of police recruits leave their academy in eastern Baghdad, killing 20.

— Jan. 28: A suicide car bomber strikes a Shiite funeral procession, killing 33 in southwestern Baghdad.

— Jan. 14: A bomb tears through a procession of Shiite pilgrims in southern Iraq, killing at least 53 people.

— Jan. 5: Coordinated bombings target Shiite Muslims, killing 78 in Baghdad and near the southern city of Nasiriyah, just days before a Shiite holy day that draws hundreds of thousands of pilgrims.

— Dec. 22, 2011: Attackers hit markets, cafes and government buildings in mostly Shiite neighborhoods of Baghdad, killing 69 people.