Al-Qaeda in the Arabian Peninsula, abbreviated as AQAP, also known as Ansar al-Sharia in Yemen, is a militant Sunni Islamist terrorist group primarily active in Yemen and Saudi Arabia that is part of the al-Qaeda network. It is considered the most active of al-Qaeda's branches that emerged after the weakening of central leadership. The U.S. government believes AQAP to be the most dangerous al-Qaeda branch. The group established an emirate during the 2011 Yemeni Revolution, which waned in power after foreign interventions in the subsequent Yemeni Civil War.