During Operation Just Cause, Operation Desert Shield and Storm, the Military Police provided area security, conducted battlefield circulation control, and exercised custody over thousands of prisoners. Since 1991, the Military Police have assisted with interventions in Somalia, Haiti and Bosnia. Military Police maintained order in war-torn Kosovo, as well as keeping the peace in Afghanistan. During the 2003 invasion of Iraq, MPs were used extensively to maintain control over the large numbers of detainees being held by coalition forces, as well as helping to conduct raids, convoy security and regular patrols. MPs were the main force responsible in rebuilding and training the Iraqi Police. Ever since the invasion, military police have been one of the most heavily engaged military occupational specialty in the Iraqi theater. In the United States, MPs often provided disaster relief and internal security, while still fulfilling their fundamental function of maintaining discipline and security within the Army.