WASHINGTON - Hajji Abd al-Nasir, an Iraqi national who served as a senior Islamic State military leader in Syria and a close confidant of its leader, Abu Bakr al-Baghdadi, has been named as a specially designated global terrorist by the United States, the U.S. State Department announced Tuesday.

Al-Nasir, also known to Interpol as Taha al-Khuwayt, was born between 1965 and 1969 in the Iraqi northern town of Tal Afar. He has held several leadership positions in the Islamic State terror group over the past five years, including working as IS's military "amir" or leader in Syria and as chair of the IS Delegated Committee.

The Delegated Committee within IS works as a council that reports to IS leader al-Baghdadi. It is responsible for planning and issuing orders about IS's military operations and has administrative control over the organization's affairs such as tax collections, religious police, and commercial and security operations.

U.S. State Department Coordinator for Counterterrorism Nathan Sales in a statement called the designation another step to ensure a lasting defeat of IS.

"ISIS is down but not out. As ISIS continues to lose ground on the battlefield, we must starve it of the resources it uses to commit terrorism around the world,' Sales said, using another acronym for the Islamic State terror group.

The militant group has been pushed out of a vast territory it once controlled across Iraq and Syria and is struggling to hold a few small pockets in eastern Syria's Deir el-Zour province.

"Today's designation seeks to deny al-Nasir the resources to plan and carry out terrorist attacks," the State Department said, adding that his property and interests subject to U.S. jurisdiction were blocked and U.S. citizens were prohibited from engaging with him.

On Monday, the U.N. Security Council also added al-Nasir to its global sanctions list.