US Secretary of State Hillary Clinton said “nothing is off the table" so long as Gaddafi threatens, kills civilians, adding that he has to leave “now without further violence or delay.”
Clinton added that Muammar Gaddafi was using "mercenaries and thugs" to suppress his own people and said the Libyan leader must step down immediately.
"Gaddafi and those around him must be held accountable for these acts, which violate international legal obligations and common decency," Clinton said in an address to the U.N. Human Rights Council in Geneva, saying nothing was off the table as the international community considers its next steps.
"It is time for Gaddafi to go, now, without further violence or delay," she added.
Meanwhile, going into exile would be one option for Libyan leader Muammar Gaddafi in meeting international demands that he leave power, White House spokesman Jay Carney said on Monday.
Carney, asked by reporters whether the United States would help facilitate exile for Gaddafi, said this was a bit of speculation that he would not discuss.
Carney also said the United States and its allies are in talks on whether to create a no-fly zone over Libya.
EU Sanctions
European Union governments earlier approved a package of sanctions against Libyan leader Muammar Gaddafi and his closest advisers on Monday, including an arms embargo and bans on travel to the bloc.
The 27 EU states also agreed to freeze the assets of Gaddafi, his family and government, and ban the sale of goods such as tear gas and anti-riot equipment that can be used against demonstrators.
The decision, approved at a meeting of EU energy ministers in Brussels, was brought forward to ensure the measures were enforced as soon as possible, the diplomats said.
European powers have called on Gaddafi, in power for more than four decades, to stand down after his attempts to suppress two weeks of anti-government protests.
Hungarian Development Minister Tamas Fellegi, whose country holds the current EU presidency, said the 27 states formally endorsed sanctions agreed by the U.N. Security Council on Saturday, which include travel bans and asset freezes.
They went further by extending the visa ban to another 10 individuals in addition to the 16 on the U.N. list and extended the asset freeze to 20 individuals in addition to Gaddafi and five family members, Fellegi told a news conference.
The measures are expected to take effect in the coming days, once the regulation is published in the EU's official journal.
Gaddafi's forces have sought to suppress a revolt that has won over large parts of the military, ended his control over eastern Libya and is holding the government at bay in western cities near the capital Tripoli.
About 400 people protested against Gaddafi in the Tajoura district in the east of the capital Tripoli on Monday, a Reuters reporter at the scene said.
Soon after, several sports utility vehicles pulled into the square where the protest was taking place and the occupants, wearing green bandanas, jumped out and fired into the air in an attempt to disperse the protest.
East of the capital, opponents of Gaddafi have held off an attack by pro-government forces near the town of Misrata and shot down a military aircraft, a witness told Reuters on Monday, as helicopters bombed a radio station in the town.
Misrata is 200 km (125 miles) east of the Libyan capital. "An aircraft was shot down this morning while it was firing on the local radio station. Protesters captured its crew," said the witness, Mohammed.
"Fighting to control the military air base (near Misrata) started last night and is still going on. Gaddafi's forces control only a small part of the base. Protesters control a large part of this base where there is ammunition."
"Misrata is still under the control of the protesters," he said.
First we have to see the end of his regime and with no further bloodshed...We want him to leave 
Rebels holding Az-Zawiyah, only 50 km (30 miles) west of Tripoli, said about 2,000 troops loyal to Gaddafi had surrounded the city, as the country's leader defied international demands that he quit to end the bloodiest of the Arab world's wave of uprisings.
"We will do our best to fight them off. They will attack soon," said a former police major who switched sides and joined the rebellion. "If we are fighting for freedom, we are ready to die for it."
Forces opposed to Gaddafi took control of several western Libyan towns as the strongman played down rebel gains as the United States said it was reaching out to Libyan opposition groups.
Oilfields under protesters
Most of Libya's oilfields are no longer under control of Gaddafi, the European Union's energy commissioner said on Monday.
"There is reason to believe most of the oil and gas fields are no longer under Gaddafi's control," Guenther Oettinger told a news conference.
"Instead we have provisional (regional) leaders who have taken control," he said, adding there was therefore no point in blockading Libyan energy shipments.
"We would be punishing the wrong people," he said.
Many of Libya's key oil producing areas and terminals are located in the east of the OPEC member state, large chunks of which have fallen to rebels seeking to oust Gaddafi.
Oettinger spoke after EU ministers approved a package of sanctions against Gaddafi and his closest advisers, including an arms embargo, asset freezes, and travel bans, in response to his attempts to suppress anti-government unrest
Protest leaders established a transitional "national council" in several eastern and western cities seized from the Gaddafi regime and called on the army to help them take the capital Tripoli.
"Any kind of assistance"
The United States had said it was prepared to offer "any kind of assistance" to Libyans seeking to overthrow Gaddafi as his opponents piece together a transitional body comprising representatives from the liberated cities.
The unrest in the oil-rich north African state has set off a "humanitarian emergency", the U.N. refugee agency UNHCR said, as almost 100,000 migrant workers fled Libya in a mass exodus of foreigners.
In a previous Clinton echoed the calls of world leaders, including President Barack Obama, for him to quit.
"We are just at the beginning of what will follow Gaddafi," she said.
"First we have to see the end of his regime and with no further bloodshed," she said, noting Washington is eager for his ouster "as soon as possible."
"We want him to leave."
Clinton's previous remarks came a day after U.S. President Barack Obama called on embattled Gaddafi to "leave now," as his country teetered on civil war, saying the Libyan leader had lost his right to rule after attacking his own people to put down a popular uprising.
Freezing Gaddafi family assets
London said it had frozen Gaddafi family assets in Britain, amid newspaper reports that these amount to around 20 billion pounds ($32.2 billion, 23.4 billion euros) in liquid assets, mostly in London.
British Prime Minister David Cameron on Sunday told Libyan leader Gaddafi that it was "time to go", saying there was no role for the long-serving ruler in the troubled country's future.
Speaking after Britain's successful mission to rescue 150 nationals from the Libyan desert, the British leader said: "All of this sends a clear message to this regime: it is time for Colonel Gaddafi to go and to go now.
"There is no future for Libya that includes him," Cameron added.
Former British leader Tony Blair, who helped bring Gaddafi back into the international fold, told Monday's Times newspaper that he rang the Libyan leader twice on Friday and said he believed the colonel was in "denial."
"What is happening shocks everyone," he told the paper. "We want to see it brought to an end."
Australia is investigating claims that Gaddafi's family has stashed millions of dollars in assets down under, Foreign Minister Kevin Rudd said Monday. Canberra has launched a forensic probe to track down any assets the crumbling regime may have secretly built up in Australia.