The United States on Friday blacklisted Ansar al-Sharia militants accused of being behind an attack on the US mission in Benghazi in 2012, in which the ambassador and three other Americans died.

Two Ansar al-Sharia groups and their leaders from the eastern Libyan cities of Benghazi and Darnah as well as a third affiliated organization from Tunisia, accused of attacking an American school in Tunis, were designated as foreign terrorist organizations, the State Department said.