WASHINGTON (Reuters) - The U.S. 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 U.S. nationals or the national security, foreign policy, or economy of the United States."
The terrorism designations are one way to deny sanctioned individuals and groups access to the U.S. financial system.
Also on Thursday, the Treasury Department said it had imposed sanctions on six individuals to disrupt the fundraising efforts of Islamic State, al Qaeda, the Nusra Front as well as al Qaeda in the Arabian Peninsula.
"Today's action targets critical al-Qaida, al-Nusrah Front, AQAP, and ISIL financiers and facilitators responsible for moving money, weapons, and people on behalf of these terrorist organizations," said Adam J. Szubin, Acting Under Secretary for Terrorism and Financial Intelligence.
The individuals include Yemen-based Nayif al-Qaysi, whom the department said was a senior AQAP official and financial supporter of the group who had obtained money for AQAP from parties outside Yemen. Another person, Mostafa Mohamed, was sanctioned for providing financial support to the Syria-based Nusra Front.
In September 2015, the United States imposed sanctions on more than 30 leaders, supporters and affiliates of Islamic State around the world.
The U.S.-led coalition fighting Islamic State has said that in addition to attacking the group's fighters and leaders, it would go after financial infrastructure.
Air strikes have reduced Islamic State's ability to extract, refine and transport oil, a major source of revenue that was already shrinking because of the drop in the price of oil.
(Writing by Yara Bayoumy; Editing by Phil Berlowitz)