The Gulf War (2 August 1990 – 28 February 1991) 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 arising from oil pricing and production disputes. It was 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.