The U.S. sanctioned the secretary-general of an Iraqi militia group Wednesday that it blames for a deadly rocket attack on a base which killed an American contractor in December. 

The designation of Ahmad al-Hamidawi as a global terrorist is intended to deny him "the resources to plan and carry out terrorist attacks," the State Department said in a statement.

Any property belonging to al-Hamidawi subject to U.S. jurisdiction has now been frozen and U.S. citizens are now generally prohibited from conducting transactions with him.

The U.S. blames al-Hamidawi's group, Kataib Hezbollah, for the Dec. 27 rocket attack on an Iraqi base near Kirkuk that killed American contractor Nawres Hamid and injured four other U.S. service members and two Iraqi security forces personnel.

The State Department further accused the militia of involvement in sniper attacks on protesters in Baghdad that killed over 100 people and injured around 6,000 others.