The US State Department said on Thursday it had designated Islamic State's branch in Libya as a "foreign terrorist organization."
The department also designated the Sunni militant group's branches in Libya, Yemen and Saudi Arabia as "specially designated global terrorists."
It said that designation "imposes sanctions and penalties on foreign persons that have committed, or pose a serious risk of committing, acts of terrorism that threaten the security of US nationals or the national security, foreign policy, or economy of the United States."