The Office of Foreign Assets Control isolated Salam under a presidential executive order for acting or representing himself to act on behalf of the younger Gadhafi and because he materially helped the son, the department said Tuesday in a release.
The designation means U.S. entities generally are barred from engaging in transactions with Salam and any assets he may have that are subject to U.S. jurisdiction are frozen.
In September and October during the popular uprising against the Gadhafi regime and after imposition of U.S. and U.N. sanctions against Moammar Gadhafi and his sons, Salam reportedly coordinated a meeting, as well as reportedly arranged the delivery of vehicles and drivers to Saadi Gadhafi and his brother, Mutassim, who died with his father after they were taken into custody in October.
Saadi Gadhafi is under house arrest in Niger, where he fled after his father's four-decade regime toppled. Salam's location wasn't provided.
Salam reportedly also was instructed by Mutassim Gadhafi to arrange payment for military equipment, including sniper rifles and night-vision devices, officials said.
"Today's designation targets a key supporter of Saadi Gadhafi, who remains determined to carry on his father's legacy, to reverse Libya's democratic transition through violence, and to foster instability in the region," said Adam Szubin, OFAC director. "The United States of America is determined to assist the Libyan people as they work to develop a democratic, peaceful, and prosperous society, and will expose those who are trying to derail Libya's transition."