Szubin, director of Treasury's Office of Foreign Assets Control, said sanctions were imposed on three Libyan state-owned companies. Under the latest measures, Americans would be banned from doing any business with these firms.

The companies were identified as Libyan Jamahiriya Broadcasting Corp., Dalia Advisory and Lafico Algeria Holdings. Dalia, based in London, is owned by the Libyan Investment Authority and has facilitated arms deals with Western and other companies.

Officials said assets of these Libyan companies were eligible for seizure in the United States. They said the administration of President Barack Obama might relay some of these assets to the Libyan rebels.

Lafico has been based in Algeria and served as a subsidiary of the Libyan Arab Foreign Investment Co. Treasury did not further identify Lafico, but officials said the latest sanctions angered Algeria, deemed an opponent of the Libyan rebel movement.

"All of their assets should be frozen," Szubin said.

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