WASHINGTON – Moments after a charter aircraft departed Libya on Friday with all remaining U.S. diplomats there, the Obama administration shuttered the U.S. Embassy in Tripoli and moved to freeze assets belonging to leader Moammar Gadhafi, his family and his inner circle.

White House officials said President Barack Obama also canceled all military contacts with Libya and ordered a reallocation of U.S. intelligence assets to focus on civilian deaths there and to track Libyan troop deployments and tank movements.

The administration had cited the risk to American lives for what had appeared to be its restrained reaction to events in Libya during the past week, even as evidence of government atrocities grew. But with virtually all Americans and other foreigners now gone, the United States moved quickly to ramp up the pressure on Gadhafi.

Its efforts were joined by those of the international community. On a day of frenetic diplomatic activity, the U.N. Human Rights Council in Geneva condemned Gadhafi’s bloody crackdown on demonstrators and ordered a war crimes investigation.

At United Nations headquarters in New York, European powers circulated a draft resolution, to be considered at an emergency Security Council meeting today, that would impose international economic sanctions on Libya and specifically target Gadhafi, his sons and his close aides with a travel ban and asset freeze.

The draft also calls for the imposition of a comprehensive arms embargo and invites the International Criminal Court to carry out an investigation into “crimes against humanity” in Libya.

Thus far, Gadhafi has shown no inclination to bow to foreign pressure. He has vowed to remain in power, and said he is ready to “die a martyr.”

Senior U.N. diplomats said there were no proposals at this time to authorize international military action or impose a no-fly zone over Libya. NATO Secretary-General Anders Fogh Rasmussen, meeting Friday with European Union defense ministers in Bucharest, said a no-fly zone would require U.N. authorization.

In a chilling briefing to the Security Council, U.N. Secretary-General Ban Ki Moon cited reports that forces loyal to Gadhafi were shooting civilians as they left their homes and inside hospitals in Tripoli, and said that more than 1,000 people had been killed.

Libya’s U.N. ambassador, Abdurraham Mohamed Shalgam, broke down in tears after he urged intervention to stop the bloodshed. Shalgam said that Gadhafi, his former friend and mentor, had given the Libyan people a grim choice: “Either I rule you or I kill you.” Shalgam received hugs from some diplomats.

Earlier in the day, his counterpart in Geneva also broke ranks with Gadhafi, calling for a minute of silence “in honor of the revolution of 17 February,” the day the demonstrations began, as other members of the Human Rights Council stood at attention.

“Colonel Gadhafi has lost the confidence of his people,” White House press secretary Jay Carney told reporters. “His legitimacy has been reduced to zero in the eyes of his people.”

But Carney said the sanctions were not intended to help push Gadhafi from power, reiterating that the Libyan people must be the ones to decide whether he should go. That has remained the U.S. public posture on the rolling “people power” revolutions that began last month in the Arab world, driving long-term leaders and U.S. allies from power in Tunisia and Egypt and sending thousands into the streets in Yemen, Bahrain and elsewhere.

Nowhere, however, have the demonstrations been met with the vicious response unleashed by Gadhafi in Libya, as opposition forces have taken over the eastern part of the country and moved toward Tripoli.

While other governments began evacuating their diplomats and citizens on ships and charter flights last week, U.S. efforts were repeatedly delayed. A ferry chartered to carry U.S. citizens and diplomats to Malta arrived on Wednesday but waited for what officials said were 18-foot waves in the Mediterranean to subside before departing Friday morning with hundreds aboard.

Carney took to the White House podium just after a final group of U.S. diplomats and civilians left for Istanbul on a charter flight from Matiga military airfield outside Tripoli on Friday afternoon.

Carney rebutted questions implying that the United States has been slow to respond to the Libya crisis, saying “there has never been a time when this much has been done this quickly.”

But Obama’s focus, he said, has been on “our obligation to the security of American citizens and also getting the policy right. And I can assure you that has been the guide — those have been the guiding principles as we’ve proceeded over the course of the last week.”

Carney said U.S. financial institutions have been told to scrutinize “private banking accounts held by or on behalf of senior foreign political figures, and to monitor transactions that could potentially represent misappropriated or diverted state assets, proceeds of bribery or other illegal payments, or other public corruption proceeds.”

Other White House officials, who spoke on condition of anonymity, said that the asset freezes and other steps designed to pressure the Libyan government to stop the violence would be formalized over the weekend.

According to State Department cables leaked by WikiLeaks, U.S. banks manage as much as a half-billion dollars in Libyan assets. The country’s main investment fund for oil profits, held largely overseas, is estimated in the tens of billions of dollars.

Long-standing U.S. sanctions against Libya had been eased in recent years as Gadhafi agreed to end his programs for weapons of mass destruction and began to cooperate in international counterterrorism efforts.

At the State Department, officials told reporters that the administration had “suspended” operations at the U.S. Embassy on Friday but has not severed diplomatic relations with Libya.