[Timeline] Key events

Following is a chronology of key events in Iraq since the U.S.-led invasion in 2003 that toppled Saddam Hussein.

2003

March 20, 2003 - U.S. and British forces invade from Kuwait.

April 9 - U.S. troops take Baghdad, Saddam disappears.

May 1 - From an aircraft carrier, Bush announces that major combat is over. A banner behind him reads "Mission Accomplished."

July 13 - The Iraqi Governing Council -- 25 Iraqis chosen under U.S. supervision -- holds inaugural meeting in Baghdad.

Dec. 13 - U.S. troops capture Saddam near Tikrit, unkempt and hiding in a hole in the ground. U.S. governor of Iraq Paul Bremer breaks news with: "We got him."

2004

March 8 - Iraq Governing Council signs interim constitution.

March: In the first major exit from the U.S.-led coalition, Spain decides to pull out its forces following devastating bomb attacks in Madrid.

April: U.S. media show photographs taken by U.S. military in Abu Ghraib prison, of Iraqi detainees being tortured by grinning American soldiers.

June 1 - Governing Council dissolved to make way for interim government led by Iyad Allawi. Ghazi al-Yawar named president. U.S. authorities declare that Iraq now enjoys sovereignty.

June 28 - United States formally returns sovereignty. Coalition Provisional Authority dissolved. Bremer leaves Iraq.

2005

January: The U.S. administration says it is giving up search for weapons of mass destruction in Iraq, having found none. The supposed presence of such weapons had been the main reason given for the invasion.

Jan. 30, 2005 - Shiite-led United Alliance dominates election for interim parliament. Most Sunnis don't vote.

March 16 - National Assembly holds first meeting.

Oct. 15 - Referendum ratifies constitution by 78 percent despite Sunni Arab opposition which nearly vetoes it. The new constitution gives wide autonomy to the country's regions, which critics see as a recipe for partition.

Oct. 19 - Saddam Hussein goes on trial charged with crimes against humanity for the killing of 148 Shiite men and boys in Dujail after a 1982 assassination attempt. He pleads not guilty.

Dec. 15 - Parliamentary elections attract wide participation, and give victory to a Shiite alliance.

2006

Feb. 10, 2006 - Final results give Shiite Alliance near majority with 128 seats. Sunnis have 58 and Kurds 53.

Feb. 22 - Destruction of Shiite shrine in Samarra sparks widespread sectarian violence, raising fears of civil war.


May 21 - New Prime Minister Nouri al-Maliki chairs first cabinet meeting.

June 7 - U.S. aircraft kill al Qaeda leader in Iraq, Abu Musab al-Zarqawi.

October - A British study concludes that 655,000 civilians have died since the invasion.

Nov. 5 - A court in Baghdad finds Saddam guilty of crimes against humanity and sentences him to hang over Dujail killings.

Dec. 30 - Saddam is hanged on the major Muslim festival of Eid al-Adha. Videos showing him being taunted by his Shiite guards are circulated on the Internet, causing fury in the Muslim world.

2007

January - Two of Saddam's former aides, Barzan Ibrahim al-Tikriti and Awad Ahmed al-Bandar are hanged.

February: Britain, the closest U.S. ally, says it will begin reducing the number of its troops in southern Iraq.

Feb 14, 2007 - Maliki launches U.S.-backed security crackdown in Baghdad aimed at pulling Iraq back from brink of civil war.

March - A political crisis begins to engulf Prime Minister Nouri al-Maliki with the departure of the Fadhila party from his Shiite coalition, the first of a series of boycotts and withdrawals from his government.

May 28 - Iranian and U.S. ambassadors to Iraq meet in Baghdad to discuss ways to improve security in the country, ending a three-decade diplomatic freeze between the two foes.

June: Ali Hassan al-Majid, otherwise known as "Chemical Ali", is sentenced to death but his execution has yet to be carried out because of a legal dispute.

June 15 - U.S. military says it has completed its troop buildup, or "surge", to 160,000 soldiers.

Aug. 1 - The main Sunni Arab bloc pulls out of Maliki's cabinet, plunging the government into crisis.

Aug. 29 - Shiite cleric Moqtada al-Sadr suspends the activities of the Mahdi Army militia for six months after clashes with police affiliated with a rival Shiite faction.

September - Private U.S. security firm Blackwater is involved in a Baghdad shooting in which 17 Iraqis are killed.

Sept. 3 - U.S. President George W. Bush makes a surprise visit to Iraq, and raises the prospect of troop cuts in the wake of falls in violence.

Sept. 10 - The U.S. military commander in Iraq, General David Petraeus, recommends cutting American troops by more than 20,000 by mid-2008 in much anticipated testimony to Congress.

Sept. 13 - Sheikh Abdul Sattar Abu Risha, a Sunni Arab tribal leader instrumental in driving al Qaeda out of Anbar province, is killed in a bomb attack.

2008

Jan. 12, 2008 - Parliament votes to let thousands of members of Saddam Hussein's Baath Party return to government jobs.

Feb. 21 - Thousands of Turkish troops cross into northern Iraq, killing 242 out of 300 targeted PKK rebels in an eight-day offensive.

March 24, 2008: The number of U.S. military dead passes the 4,000 mark.