The US stepped up the drive for sanctions against Libya, consulting Britain, France and Italy on how to respond to Gaddafi's crackdown.
Switzerland ordered an immediate freeze on any assets that may belong to the Libyan strongman and his entourage.
Hundreds of people have been killed amid a brutal crackdown by Gaddafi's forces since the uprising started in the eastern city of Benghazi on February 15, according to witnesses and rights groups. Some politicians say the toll could be as high as 1,000.
US and allies crank up pressure on Gaddafi
Washington also called on the UN Human Rights Council to dump Libya and nervously awaited the weather-delayed sailing of a chartered ferry set to carry 285 Americans and other foreigners from violence-wracked Tripoli to Malta.
The Obama administration had been accused of reacting too slowly to the onslaught of violence against civilian demonstrators in Libya, but sought Thursday to frame an international response to the Libyan leader's purge.
President Barack Obama called British Prime Minister David Cameron, French President Nicolas Sarkozy and Italian Prime Minister Silvio Berlusconi, to seek urgent ways to ensure "appropriate accountability" for the Libyan government.
Obama discussed the need for "effective" ways for the world to respond "immediately" to violence that had violated all international norms, the White House said in a statement.
Cameron's office said the leaders agreed to coordinate multi-lateral responses and help one another extricate their expats from Libya.
Sarkozy's office said after his call with Obama that France would "demand a new urgent meeting of the UN Security Council on the situation in Libya."
Officials would not say exactly what punishments Libya could expect after unleashing violence on anti-regime demonstrators that some reports say has killed 1,000 people, in the latest wave of unrest in the tumultuous Middle East.
But they stressed that no option had been ruled out.
"We're examining a lot of options. Sanctions are one of them," White House spokesman Jay Carney said, amid reports that economic sanctions, asset freezes and even a "no fly zone" to protect civilian leaders were under discussion.
State Department spokesman Philip Crowley said that the US military had been a "full participant" in discussions about options to present to Obama.
But officials also stressed the extreme sensitivity of the situation.
"Whatever steps that we do take, we want them to be effective. And we certainly don't want to take any actions that put either our citizens or the citizens of other countries at risk," Crowley said.
Crowley also called on the Geneva-based rights council to expel Libya, ahead of an unprecedented meeting of the world's top human rights body to discuss measures to take against one of its own members on Friday.
On Monday, US Secretary of State Hillary Clinton will join a ministerial meeting at the council.
The diplomatic flurry came on a day when Gaddafi claimed in a new tirade that opponents of his four-decades-old rule were "trigger-happy" youths "stoned with drugs" and inspired by Osama bin Laden.
US officials declined to be drawn on the tirade.
The details of direct US contacts with parts of the apparently teetering Gaddafi regime did emerge, including an apparent attempt by the volatile Libyan strongman to contact Washington.
The number three ranked State Department official, William Burns, who was heading from Algiers to Rome Thursday, spoke twice with Libyan Foreign Minister Musa Kusa to express gratitude for cooperation shown in helping with the evacuation, Crowley said.
Crowley said there had been no attempt by Washington to contact Kadhafi directly, but added: "That said, in the various contacts that we've had with Libyan officials, they have actually passed messages to us from Mr. Gaddafi."
US officials said privately that Obama's circumspect tone on the crisis, which sparked criticism at home, had been motivated by fears that Americans trapped by the violence could face reprisals.
The chartered ferry riding out stormy weather in Tripoli harbor has 285 passengers aboard, including 40 US diplomats and family members, 127 other Americans and 118 foreigners also fleeing the raging political violence, officials said.
"The Libyans are securing their port, at which the ship is docked. We have security officials on board the ship as well," Crowley said.
The vessel had originally been scheduled to cast off on Wednesday.
Washington also hopes to run a charter flight into Libya on Friday to pick up more fleeing Americans.
There was also concern about the impact of spiking oil prices on the US economic recovery, with three Democratic lawmakers calling on Obama to tap the US strategic stockpile of oil reserves to control gasoline prices.
Carney, however, played down any immediate fears that Libya's turmoil could disrupt global oil supplies in the short term.
"We are in touch with the IEA (International Energy Agency) and we have the capacity to act in the event of any particular supply disruption," he said.
