Many countries, including the United States and the European Union have accused the Syrian government of conducting several chemical attacks. Following the 2013 Ghouta attacks and international pressure, Syria acceded to the Chemical Weapons Convention and the destruction of Syria's chemical weapons began. In 2015 the UN mission disclosed previously undeclared traces of sarin compounds in a "military research site". After the April 2017 Khan Shaykhun chemical attack, the United States launched its first attack against Syrian government forces. On 14 April 2018, the United States, France and the United Kingdom carried out a series of joint military strikes against multiple government sites in Syria, including the Barzah scientific research centre, after a chemical attack in Douma.