The First Battle of Fallujah, code-named 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.