The First Battle of Fallujah, also known as Operation Vigilant Resolve, was an operation against militants in Fallujah as well as an attempt to apprehend or kill the perpetrators of the killing of four U.S. contractors in March 2004.
The chief catalyst for the operation was the highly publicized killing and mutilation of four Blackwater USA private military contractors, and the killings of five American soldiers in Habbaniyah a few days earlier.
The battle polarized public opinion within Iraq.
The Second Battle of Fallujah—code-named Operation Al-Fajr (Arabic: الفجر "the dawn") andOperation Phantom Fury—was a joint American, Iraqi government, and British offensive in November and December 2004, considered the highest point of conflict in Fallujah during the Iraq War. It was led by the U.S. Army and U.S. Marines against the Iraqi insurgents in the city of Fallujah and was authorized by the U.S.-appointed Iraqi Interim Government. The U.S. military called it "some of the heaviest urban combat U.S. Marines and Soldiers have been involved in since the Battle of Hue City in Vietnam in 1968."
This operation was the second major operation in Fallujah. Earlier, in April 2004, coalition forces fought the First Battle of Fallujah in order to capture or kill insurgent elements considered responsible for the deaths of a Blackwater Security team. When coalition forces fought into the center of the city, the Iraqi government requested that the city's control be transferred to an Iraqi-run local security force, which then began stockpiling weapons and building complex defenses across the city through mid-2004. The second battle was the bloodiest battle of the entire Iraq War, and is notable for being the first major engagement of the Iraq War fought solely against insurgents rather than the forces of the former Ba'athist Iraqi government, which was deposed in 2003.