A look at some of the deadliest days of attacks in Iraq since the war began March 20. President Bush declared major combat over on May 1.

—Jan. 17, 2004: Number of American service members who have died reaches 500 after roadside bomb explodes near Baghdad, killing three U.S. soldiers and two Iraqi civil defense troopers.

—Jan. 9: Bomb explodes as worshippers leave Shiite mosque, killing five people and wounding dozens. Police defuse car bomb outside another nearby mosque.

—Jan. 8: U.S. Black Hawk medevac helicopter apparently shot down, crashes near Fallujah killing all nine soldiers aboard.

—Dec. 31, 2003: Car bomb rips through restaurant holding crowded New Year's Eve party, killing eight Iraqis, wounding 35.

—Dec. 27: Suicide bombers and assailants with mortars and grenade launchers blast coalition military bases and governor's office in coordinated attacks in southern city of Karbala, killing 19 people, wounding nearly 200.

—Dec. 14: Suspected suicide bomber detonates explosives in car outside police station west of Baghdad, killing at least 17, wounding 33.

—Nov. 29: Assailants ambush team of Spanish intelligence agents, killing seven. Two Japanese diplomats shot to death after insurgents ambush their car near Tikrit.

—Nov. 22: Attackers strike two police stations with back-to-back car bombings northeast of Baghdad, killing at least 12 Iraqi bystanders.

—Nov. 20: Truck bomb explodes near Kurdish party office in northern oil city of Kirkuk, killing five people, wounding 30. Local officials blame Islamic extremists linked to al-Qaida.

—Nov. 15: Two Black Hawk helicopters collide and crash in Mosul, apparently hit by ground fire, killing 17 American soldiers. U.S. military's worst single loss of life in Iraq conflict.

—Nov. 12: Suicide truck bomber attacks headquarters of Italy's paramilitary police in southern city of Nasiriyah, killing more than 30 people — including 19 Italians.

—Nov. 7: Army Black Hawk helicopter apparently downed by rocket-propelled grenade, killing six U.S. soldiers aboard.

—Nov. 2: U.S. Chinook helicopter carrying troops headed for leave is struck by missile and crashes west of Baghdad, killing 15 soldiers, wounding more than 20.

—Oct. 27: Four suicide bombings target International Red Cross headquarters and four Iraqi police stations in Baghdad, killing 40 people, mostly Iraqis.

—Oct. 9: Suicide bomber drives Oldsmobile into police station in Baghdad's Sadr City district, killing nine bystanders.

—Sept. 12: U.S. forces kill eight Iraqi police and Jordanian security guard, wound nine others. Deadliest friendly fire incident since major combat declared over.

—Aug. 29: Car bomb explodes outside mosque in Shiite Muslim holy city of Najaf, killing more than 85 people including Shiite leader Ayatollah Mohammed Baqir al-Hakim.

—Aug. 19: Truck bomber strikes United Nations headquarters in Baghdad, killing 23 people including top U.N. envoy to Iraq, Sergio Vieira de Mello.

—Aug. 7: Car bomb explodes outside Jordanian Embassy, killing 19 people including two children.

—June 24: Firefight kills six British soldiers training police in southern Iraq. Eight others wounded when Iraqis ambush patrol and helicopter.

—April 7: U.S. warplanes strike convoy of allied Kurdish fighters and U.S. Special Forces during northern battle, at least 18 killed, more than 45 wounded.

—April 3: Eleven U.S. soldiers killed in combat or die in accidents. The day before, 10 American soldiers died.

—March 23: Deadliest day for U.S. soldiers, with 28 Americans killed. Toll includes 11 killed when 507th Maintenance Company convoy ambushed in Nasiriyah. Nine wounded and seven captured, including Pvt. Jessica Lynch.

—March 21: Eight British soldiers and four U.S. Marines killed when helicopter crashes in Kuwait.