Ansar al-Sharia is listed as a foreign radical organisation by Washington and it was accused of orchestrate the 2012 attack on the US consulate in Benghazi in which US Ambassador Chris Stevens and three other Americans died.
Mohamed Zahawi, head of the Benghazi brigade of Ansar al-Sharia, charged the US government of supporting renegade former general Khalifa Haftar, who has begun a self-declared campaign to purge Libya of militancy.