Timeline of US involvement in Iraq

October 2002 -- Congress agrees on U.S. involvement in Iraq and President George W. Bush signs authorization of military force on Oct. 16, 2002.

March 19, 2003 -- The U.S. launches an attack against Iraq after a deadline for Iraqi President Saddam Hussein expires.

April 9, 2003 -- American forces in Baghdad topple a statue of Saddam Hussein, signaling the end of an era for the leader.

May 1, 2003 -- President Bush, speaking on the USS Abraham Lincoln, says major combat operations in Iraq will be ended.

December 13, 2003 -- Saddam Hussein is captured after being found hiding inside a hole outside of his hometown of Tikrit.

April 2004 -- Images emerge of prisoner abuse by American military personnel at the Abu Ghraib prison.

June 28, 2004 -- The U.S.-led coalition hands over power to the interim Iraq government.

November 2004 -- The U.S. leads a major offensive against insurgents in the city of Fallujah.

December 30, 2006 -- Saddam Hussein is hanged after being found guilty in Iraqi courts of crimes against humanity.

January 10, 2007 -- President Bush announces the deployment of 30,000 additional troops to Iraq.

November 2008 -- Iraq’s parliament approves a security pact with the U.S. that calls for the removal of all American troops by the end of 2011.

October 2011 -- President Barack Obama announces end of Iraq war. He says troops will be withdrawn by the end of the year.

December 2011 -- Final U.S. troops leave Iraq.

January 2014 -- Al Qaeda-inspired militants from the Islamic State of Iraq and the Levant – also known as the Islamic State of Iraq and Syria (ISIS) – capture the city of Fallujah and other territory in the Sunni-dominated Anbar province, which lies west of Baghdad.

April 2014 -- Iraqis vote in the first parliamentary elections with the withdrawal of U.S. troops.

June 10, 2014 -- The ISIS overrun parts of the country’s second largest city, Mosul. An estimated 500,000 people flee from the city as security forces abandoned their posts.

June 11, 2014 -- The ISIS takes control of Saddam Hussein's hometown of Tikrit, as soldiers and security forces once again abandon their posts.

June 12, 2014 -- The ISIS vows to march onward to Iraq’s capital, Baghdad.