Here is a look at the deadliest attacks in Iraq since the withdrawal of U.S. troops on Dec. 18, 2011:
— May 20, 2013: A wave of attacks, some at markets and rush hour crowds, hour killed at least 86 people in Shiite and Sunni areas.
— May 18, 2013: Shootings and bombings kill at least 16 people including an anti-terrorism police captain and his family.
— May 17, 2013: Bombs rip through Sunni areas in Baghdad and surrounding areas, killing at least 76 people.
— May 16, 2013: Car bombs hit Shiite neighborhoods in Baghdad and attacks elsewhere in the country leave 21 people dead.
— May 15, 2013: A car bomb goes off near a bus station in Baghdad's main Shiite district, the deadliest of explosions that killed at least 33 people nationwide.
— May 14, 2013: A convoy of gunmen open fire on a row of liquor stores in eastern Baghdad, killing 11 people and wounding five others.
— April 29, 2013: A wave of car bomb blasts tear through Shiite areas south of Baghdad, killing at least 36.
— April 25, 2013: More than 40 people were reported killed in fighting in the key northern city of Mosul.
— April 24, 2013: Clashes between the army and armed Sunni tribesmen who sealed off a central Iraqi town kill 22 people.
— April 23, 2013: Security forces storm a Sunni protest camp in the north, sparking deadly clashes in several towns, which combined with other attacks left 56 people dead.
— April 18, 2013: A suicide bomber detonated explosives at a Baghdad cafe crowded with young people, killing 32
— April 15, 2013: At least 36 are killed in string of attacks across the country ahead of elections.
— April 6, 2013: A suicide bomber blows himself up at a lunch hosted by a Sunni candidate ahead of regional elections, killing 20 people.
— Mar. 19, 2013: Insurgents carry out a wave of bombings that kills at least 65 people on the eve of the 10th anniversary of the U.S.-led invasion. An al-Qaida in Iraq front group claimed responsibility.
— Mar. 14, 2013: Militants unleash a carefully planned assault on the Justice Ministry, killing 30.
— Mar. 4, 2013: Gunmen attack a convoy of Syrian soldiers who had crossed into Iraq for refuge, killing 48.
— Feb. 17, 2013: Car bombs tear through shopping areas in Shiite neighborhoods in Baghdad, killing at least 37.
— Jan. 23, 2013: A suicide bomber strikes a packed funeral ceremony at a Shiite mosque in northern Iraq, killing at least 25.
— Jan. 17, 2013: Insurgents unleash a string of bomb attacks mainly targeting Shiite Muslim pilgrims across Iraq, killing at least 26.
— Jan. 16, 2013: A wave of bombings against the offices of a major Kurdish party and Kurdish security forces headquarters in Kirkuk province kills at least 33.
— Nov. 27, 2012: Insurgents launch attacks against Shiite mosques, security forces, and other targets in central and northern Iraq, killing at least 30.
— Nov. 6, 2012: A suicide bomber detonates his explosives-laden car near a military base north of Baghdad, killing at least 33.
— Sept. 9, 2012: Insurgents gun down soldiers at an army post, bomb police recruits waiting in line to apply for jobs, and stage other attacks that kill 92.
— Aug. 16, 2012: A blistering string of bombings and shootings across the country kills at least 93.
— July 23, 2012: Attacks aimed largely at security forces kill 115 in the country's deadliest single day in two years.
— July 3, 2012: Bombs pound six cities and towns, killing some 40 and raising suspicion that security forces may be assisting attacks on Shiites.
— June 28, 2012: Bombings and shootings take the lives of 22 people in attacks in Shiite neighborhoods and on security forces.
— June 16, 2012: Two car bombs kill at least 26 people in the capital on the final day of the Shiite pilgrimage.
— June 13, 2012: Car bombs target an annual Shiite pilgrimage, killing 72 people in 16 separate explosions.
— June 4, 2012: A suicide car bomb hits 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, 2012: Bombs rip through 10 Iraqi cities, killing at least 30 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, 2012: 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, 2012: Assailants waving al-Qaida's battle flag gun down 25 policemen in a brazen, well-orchestrated attack in Haditha, challenging government control over the town in Iraq's Sunni-dominated west.
— Feb. 23, 2012: Attackers kill at least 55 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, 2012: A suicide bomber detonates his car as a group of police recruits leave their academy in eastern Baghdad, killing 20.
— Jan. 28, 2012: A suicide car bomber strikes a Shiite funeral procession, killing 33 in southwestern Baghdad.
— Jan. 14, 2012: A bomb tears through a procession of Shiite pilgrims in southern Iraq, killing at least 53.
— Jan. 5, 2012: Coordinated bombings target Shiite Muslims, killing 78 in Baghdad and near the southern city of Nasiriyah, just days before a Shiite holy.
— Dec. 22, 2011: Attackers hit markets, cafes and government buildings in mostly Shiite neighborhoods of Baghdad, killing 69.