The United States has added the Islamic State group's branches in Libya, Yemen and Saudi Arabia to its global terrorism blacklist, the State Department announced Thursday.

The three IS branches were declared "specially designated global terrorists," which imposes sanctions and penalties on foreign persons who pose a serious risk of committing acts of terrorism that threaten US nationals or national security.

The State Department said the three groups emerged as IS branches in November 2014 when IS leader Abu Bakr al-Baghdadi announced he had accepted oaths of allegiance from fighters in Libya, Yemen and Saudi Arabia.