"Today's designation of Moussa Koussa builds on the strong steps taken by the US to apply targeted, financial pressure on the Gaddafi regime," acting Under Secretary for Terrorism and Financial Intelligence David S Cohen said.
"The identification of state-owned companies furthers Libya's isolation from the US financial system," Cohen said.
Moussa Koussa, who previously served as the Libya's intelligence chief, was designated pursuant to a US President's Executive Order, which targets, among others, senior officials of the government of Libya.
As a result of today's designation, any assets of Koussa subject to US jurisdiction are frozen, and US persons are prohibited from engaging in business with him.
The 16 Libyan government entities include Afriqiyah Airways, National Oil Corporation, Libya Investment Authority, Libya Africa Investment Portfolio, Libyan African Investment Company, Libyan Arab Foreign Investment Company.
Libya Arab Foreign Bank, Economic and Social Development Fund Company, Gomhouria Bank, Al Wafa Bank, Agricultural Bank, National Commercial Bank, National Banking Corporation, Sahara Bank, Savings and Real Estate Investment Bank and First Gulf Libyan Bank.
The latest sanctions blocks all property and interests in property of the government of Libya and its agencies, instrumentalities and controlled entities.
The announcement was made a day after, US President Barack Obama issued a fresh ultimatum to Gaddafi to leave as he has lost legitimacy. "Mr Gaddafi has lost legitimacy and he needs to leave," Obama said yesterday.