WASHINGTON - The Obama administration is freezing assets held by Libyan leader Moammar Gadhafi and four of his children in the United States.
The Treasury Department says the sanctions against Gadhafi, three of his sons and a daughter also apply to the Libyan government.
The action was taken under an executive order signed Friday by President Barack Obama.
Obama says the U.S. is imposing unilateral sanctions on Libya because continued violence there poses an "unusual and extraordinary threat" to America's national security and foreign policy.
The president acted after hundreds of Americans were safely evacuated from Libya following days of bloodshed across the country. Militias loyal to Gadhafi have been firing on protesters who have been demanding the Libyan leader's ouster.
White House spokesman Jay Carney said President Obama will meet with the United Nations secretary general in Washington on Monday to discuss the situation in Libya.
Libya, which Transparency International ranks among the world's most corrupt countries, has enormous assets to plunder. According to a confidential U.S. State Department cable posted by WikiLeaks, the head of the Libyan Investment Authority said last year that "several" United States banks manage between $300 million and $500 million in Libyan assets. According to the cable, Mohamed Layas told U.S. Ambassador Gene Kretz that the country's so-called sovereign wealth fund, which invests Libya's enormous oil profits, had $32 billion in cash and other liquid assets.
The Sovereign Wealth Fund Institute, a Canadian research organization, estimates that Libya's Investment Authority controls total assets of $70 billion, making it the 13th largest such fund in the world.
The U.S. maintained a stiff embargo against Libya, but in recent years had begun easing some restrictions as a result of Qaddafi's willingness to cooperate in ending his nuclear ambitions and aiding in counterterrorism efforts.
He said that U.S. intelligence agencies would closely monitor Libyan officials for any evidence of involvement in human rights violations. "We want to make sure that violations of human rights are held accountable," he said.
A U.S. official said the Tripoli embassy's operations were suspended when a chartered flight took the last embassy staff out of the country at 1:49 p.m. That followed a ferry that departed earlier Friday for Malta with 300 Americans aboard.
The official, who spoke on condition of anonymity because of the sensitivity of the situation, said the embassy was shut down because of the deteriorating security situation in Libya, where protests against Qaddafi's 42-year rule have become an armed insurrection.
"Any strategy to compel a leader attempts to put at risk the things that he values: his power, his money, his family," CBS News national security analyst Juan Zarate said Thursday.
Mr. Obama was briefing world leaders on U.S. plans and coordinating international pressure on Qaddafi's government to stop violence against opponents. International officials say thousands may be dead.
The president spoke Friday with Turkish Prime Minister Recep Tayyip Erdogan and they discussed measures to hold Libya's government accountable for its "unacceptable" violence, the White House said. Mr. Obama spoke with leaders from the United Kingdom, France and Italy on Thursday.
The U.S. moves follow Thursday's order by the Swiss government blocking any assets in Switzerland belonging to Qaddafi.
In Geneva, U.S. diplomats joined a unanimous condemnation of Libya at the U.N. Human Rights Council. Countries there also agreed to establish an investigation into possible crimes against humanity in Qaddafi's crackdown on protesters and recommended that Libya be suspended from the body.
The U.N. Security Council in New York was expected to discuss the situation in the Arab country later Friday. NATO is discussing deploying ships and surveillance aircraft to the Mediterranean Sea.