WASHINGTON (Reuters) - The U.S. Treasury Department on Thursday placed two alleged leaders of the militant group Nusra Front in Syria on its sanctions blacklist.

U.S. authorities said the two men, Iyad Nazmi Salih Khalil and Bassam Ahmad al-Hasri, helped oversee Nusra’s operations in Syria, the Treasury Department said in a statement.

The U.S. action orders American companies to cut off all ties with the men and freeze any assets.

As of last year, Khalil was the group’s third-highest ranking official, strengthened its security and intelligence operations responsible for assassinations and ran prisons notorious for torture, U.S. authorities said.

While controlling less territory and manpower than Islamic State, U.S. officials view Nusra as a continuing threat in Iraq and Syria. Nusra now calls itself Jabhat Fateh al-Sham, since severing its ties with al Qaeda last year.

Separately, the U.S. Treasury Department blacklisted a Syria-based company, Mechanical Construction Factory, for its alleged ties to a Syrian government agency that produced non-conventional weapons.