Since the United States declared the end of major combat operations in Iraq in May 2003, the violence in the country has been escalating. Following are the major bomb attacks in postwar Iraq:

Aug. 19, 2003 -- A truck bomb rips through the UN headquarters in Iraq, killing 24 people, including UN special envoy to Iraq Vieira de Mello, and wounding 100 others.

Aug. 29, 2003 -- A car bomb hits the Imam Ali mosque in the Iraqi city of Najaf, killing more than 100 people, including leading Shiite cleric Ayatollah Mohammad Baqer al-Hakim, and injuring 200 others.

Oct. 27, 2003 -- A string of bomb attacks strike the International Red Cross headquarters and four police stations in Baghdad, killing 35 people and injuring 200 others.

Nov. 12, 2003 -- About 19 Italians and eight Iraqis are killed after a massive two-vehicle blast guts the barracks housing Italy's Carabinieri police force in the southern Iraqi town of Nassiriya.

Dec. 27, 2003 -- Insurgents carry out the most devastating offensive against the US-led coalition forces and Iraqi police in Iraq's southern city of Karbala, killing 19 people and wounding 129 others.

Jan. 18, 2004 -- About 24 people are killed and 120 others injured in a suicide car bombing, which occurs outside the compound housing offices of the interim Iraqi Governing Council and the US-led coalition in central Baghdad.

Feb. 1, 2004 -- Twin suicide bomb attacks hit the northern Iraqi city of Irbil, killing at least 109 people and wounding 133 others.

Feb. 10, 2004 -- A car bomb attack hits a police station in the central Iraqi town of Iskandariyah, some 40 km south of Baghdad, killing at least 55 people and wounding 60 others.

Feb. 11, 2004 -- About 46 people are killed and 54 others injured when a car bomb explodes near an army recruiting center in Baghdad.

March 2, 2004 -- A total of 271 people are killed and 500 others injured as a result of multiple bombings at Shiite Muslim holy shrines in Iraq.

April 4, 2004 -- Supporters of prominent Iraqi Shiite cleric Moqtada al-Sadr wage violent resistance against US forces in Baghdad and other cities.

April 5, 2004 -- The US forces cordon off the restive city of Fallujah, west of Baghdad, waging a new military operation named "Vigilant Resolve."

About 700 Iraqis and 135 US soldiers had been killed in violent clashes between the Mehdi militia and the coalition forces.

April 21, 2004 -- Suicide bombers kill at least 69 people and wounded 30 others in coordinated strikes on three police stations and one police academy in Iraq's southern city of Basra.

May 17, 2004 -- Izzedin Salim, rotating president of the US-appointed Iraqi Governing Council, is killed by a car bomb at a checkpoint in Baghdad.

June 17, 2004 -- At least 35 people are killed and 119 others injured as a car, packed with artillery shells, drives into a crowd and explodes at an Iraqi recruiting center in western Baghdad.

July 28, 2004 -- A suicide car bomb explodes outside a police recruiting center in the Iraqi city of Baquba, killing 68 Iraqis and wounding 70 others.

Sept. 14, 2004 -- About 47 people are killed and 114 others wounded in a car bomb blast near a police station in Haifa street in central Baghdad.

Sept. 30, 2004 -- A string of bomb attacks rock Baghdad, killing at least 49 people and wounding 200 others.

Nov. 6, 2004 -- At least 37 people are killed and 62 others wounded in four car bomb explosions in the Iraqi city of Samarra.

Nov. 8, 2004 -- The US forces, backed by Iraqi troops, kick offan all-out offensive on Iraq's rebel-held city of Fallujah.

Thousands of families fled the city to avoid the violent clashes. Some 71 US troops were killed in Iraq's Fallujah in the week-long battle to control the city.

Dec. 19, 2004 -- About 62 people are killed and 130 others wounded in two car bomb blasts in the Iraqi Shiite holy cities of Najaf and Karbala.

Dec. 21, 2004 -- Twenty-two people are killed and 69 others wounded in one of the deadliest guerrilla attacks on a US militarybase in Iraq's northern city of Mosul.