The Gulf War (2 August 1990 – 28 February 1991), codenamed Operation Desert Shield (2 August 1990 – 17 January 1991) for operations leading to the buildup of troops and defense of Saudi Arabia and Operation Desert Storm (17 January 1991 – 28 February 1991) in its combat phase, was a war waged by coalition forces from 35 nations led by the United States against Iraq in response to Iraq's invasion and annexation of Kuwait.