Here is a timeline of some of the deadliest attacks in Iraq in the last year:
Jan. 25, 2010 - Three suicide bombs hit the Babylon, the (Sheraton) Ishtar, and al-Hamra hotels in Baghdad. At least 36 are killed. Al Qaeda-linked insurgents claim responsibility.
Feb. 1 - A female suicide bomber blows herself up among Shi'ite pilgrims starting a trek to Kerbala for the religious rite of Arbain. At least 41 people are killed and 106 wounded.
April 23 - Thirteen blasts hit different areas of Baghdad around the time of Muslim prayers, mostly near Shi'ite mosques and at a marketplace, killing at least 56 people. Eight people are killed by bombs in the Sunni west of the country.
May 10 - Two suicide car bombers drive into the entrance of a textile factory in Hilla, 100 miles (60 km) south of Baghdad, killing at least 35 people and wounding 136.
-- Earlier, a suicide bomber wearing a vest laden with explosives and another driving a car kill at least 13 people and wound 40 in al-Suwayra, 50 km (30 miles) southeast of Baghdad.
-- In all, around 125 people are killed across Iraq with more than 200 wounded.
July 18 - A suicide bomber attacks government-backed Sunni militia as they line up to be paid on Baghdad's southwestern outskirts, killing at least 39 and wounding 41.
-- Four other anti-al Qaeda militia members are killed by a suicide bomber in western Iraq, near the Syrian border.
Aug. 7 - At least two explosions strike the popular market in the centre of Basra killing at least 45 and wounding up to 200 people.
Aug. 17 - Suicide bombers strike outside an army recruitment centre near Maidan square in Baghdad, killing at least 57 people and wounding 123. On Aug 20, the Islamic State of Iraq (ISI), an al Qaeda umbrella group, claims responsibility.
Oct. 31 - Gunmen linked to an Iraqi al Qaeda group seize hostages during Sunday mass at the Our Lady of Salvation Church in Baghdad during Sunday mass. Around 52 hostages and police are killed and 67 wounded in the incident that ended when security forces raid the church to free around 100 Iraqi Catholics. Al Qaeda's Iraqi affiliate, the Islamic State of Iraq, claims responsibility for the attack on "the dirty den of idolatry". Nov. 2 - A series of bombs rocks mainly Shi'ite areas of Baghdad, killing at least 64 people and wounding around 360 people.
Jan. 18, 2011 - A suicide bomber attacks Iraqi police recruits in Tikrit, killing 50 people and wounding over 100.
Jan. 27 - A car bomb explosion at a funeral wake in a Shi'ite neighbourhood in Baghdad kills more than 45 people and wounded scores of others.
March 29 - At least 53 people are killed and 98 wounded when gunmen take hostages at a provincial council headquarters in Saddam Hussein's hometown of Tikrit, precipitating a battle with security forces who swept in to end the siege.