2003    Secretary of State for Foreign and Commonwealth Affairs Robin Cook, resigns from the British Cabinet in disagreement with government plans for the 2003 invasion of Iraq.

2003    2003 invasion of Iraq: In the early hours of the morning, the United States and three other countries begin military operations in Iraq.

2003    In Nasiriyah, Iraq, 11 soldiers of the 507th Maintenance Company as well as 18 U.S. Marines are killed during the first major conflict of Operation Iraqi Freedom. 654 Iraqi combatants are also killed.

2003    In a "friendly fire" incident, two A-10 Thunderbolt II attack aircraft from the United States Idaho Air National Guard's 190th Fighter Squadron attack British tanks participating in the 2003 invasion of Iraq, killing British soldier Matty Hull.

2003    2003 invasion of Iraq: Baghdad falls to American forces;Saddam Hussein statue topples as Iraqis turn on symbols of their former leader, pulling down the statue and tearing it to pieces.

2003    2003 invasion of Iraq: In what becomes known as the "Mission Accomplished" speech, on board the {{USS|Abraham Lincoln|CVN-72|6}} (off the coast of California), U.S. President George W. Bush declares that "major combat operations in Iraq have ended".

2003    Iraq war: In Nasiriya, Iraq, at least 23 people, among them the first Italian casualties of the 2003 Iraq war, are killed in a suicide bomb attack on an Italian police base.

2004    War in Iraq: Al-Qaeda carries out the Ashoura Massacre in Iraq, killing 170 and wounding over 500.

2004    ''The New York Times'' publishes an admission of journalistic failings, claiming that its flawed reporting and lack of skepticism towards sources during the buildup to the 2003 war in Iraq helped promote the belief that Iraq possessed large stockpiles of weapons of mass destruction.

2004    War in Iraq: The interim government of Iraq calls for a 60-day "state of emergency" as U.S. forces storm the insurgent stronghold of Fallujah.

2004    War in Iraq: More than 10,000 U.S. troops and a small number of Iraqi army units participate in a siege on the insurgent stronghold of Fallujah.