Latest PHOTOS: Noose tightens around Gaddafi

Embattled Libyan dictator Muammar Gaddafi was pushed further to the brink as opposition forces stormed closer to the capital Tripoli and the international community stepped up pressure on him to leave the country to bring an end to the fighting that has claimed at least 1,000 lives.

Unrest continued in and around the capital, with three key areas close to the east of Tripoli falling to opposition forces advancing from Az-Zawiyah, just 50 km west of the capital, Al-Jazeera channel reported.

As rebels fought government forces trying to take back strategic coastal cities on either side of the capital Tripoli, Libyan air force planes reportedly attacked ammunition depots in two separate locations south of opposition-held second city Benghazi. Two planes also attacked a munitions dump at Rajma. There were no reports of casualties in the raids.

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As the anti-Gaddafi forces moved close to Tripoli for a final showdown with militia still loyal to Gaddafi, the US and its European allies readied plans for a possible imposition of a 'no-fly zone' over the embattled country.

"Gaddafi was reported to be holed up in the heavily fortified Bab al-Aziziya area of the capital with his mercenaries militia men ringing him," the channel said.

Quoting its correspondent moving with the opposition forces, the channel said heavily armed Gaddafi's forces were manning check-posts between Az-Zawiyah and Tripoli.

It said there were also reports of Gaddafi loyalists demonstrating in small towns on the periphery of the capital. It claimed that Gaddafi loyalists were also venturing to launch probing attacks outside the capital and said that at the moment "the capital was still in his control".

As Gaddafi and opposition forces seemed to be locking into a final battle, US and its European allies appeared to be stiffening their attitude to fast paced developments in Libya.

In a tough message, US Secretary of State Hillary Clinton asked Gaddafi to leave the country and end his regime as soon as possible.

"We think he must go as soon as possible without further bloodshed and violence," Clinton told reporters as she headed towards Geneva to attend the UN Human Rights Council meeting on Monday.

"We want him to leave and we want him to end his regime and call off the mercenaries and those troops that remain loyal to him. How he manages that is obviously up to him and to his family," Clinton said.

Obama administration officials were in talks with European and other allied governments for a possible imposition of 'no-fly zone' over Libya to prevent further killings of civilians by troops loyal to Gaddafi, New York Times reported.

US officials are also discussing whether the American military could move to disrupt communications to prevent Col Gaddafi from broadcasting in Libya.

British Prime Minister David Cameron asked Gaddafi that it was "time to go". "There is no future for Libya that includes him," Cameron added.

Britain, which has already revoked Gaddafi's diplomatic immunity on Monday, has frozen assets worth about 20 billion pounds that the Libyan leader and his family held in the country.

British Foreign Secretary William Hague said Libya had "failed shamefully in its responsibilities to its people".

The BBC quoted Russian Foreign Minister Lavrov as saying that the use of military force against the civilian population was "unacceptable".

Catherine Ashton, the foreign policy chief of EU, said the organisation had agreed to slap an asset freeze and travel ban on Gaddafi and 25 members of his family and inner circle.

She said the EU will meet to implement UN sanctions against Libya as well as other restrictions.

UN Secretary General Ban Ki Moon was scheduled to meet US President Barack Obama in White House to discuss the deteriorating situation in Libya.

France on Monday declared it would send "massive" aid to opposition-held territories in Libya and did not rule out supporting the NATO enforcement of a no-fly zone.

The French Prime Minister Francois Fillon said the country's air force plane would start leaving for Benghazi to start a massive humanitarian and relief operations.

The French announcement followed as British and German military planes flew clandestinely into the Libyan desert rescuing hundreds of civilians stranded in the country.

The dramatic rescue by planes came after a secret commando raid by Britain's famed SAS, which plucked 150 oil workers from multiple locations from the remote Libyan desert, The Sunday Telegraph reported.

The paper quoting unnamed Whitehall officials said the secret military mission into the strife torn country signalled the readiness of western nations to disregard Libya's territorial integrity when it comes to the safety of its citizens.

Three British Royal Air force C130 Hercules Aircraft swooped into the eastern Libyan desert to pluck out 150 stranded civilians and flew them to safety to Malta on Sunday, the British Defence Secretary Liam Fox said in a statement.

Telegraph said, one of the RAF Hercules transport aircraft suffered minor damages from small arms fire.

In a similar defiant action, Germany said its air force transport planes had evacuated 132 people from the Libyan desert during a secret military mission on Saturday.

The sanctions included asset freezes for 68-year-old Gaddafi and his family, travel ban for the Libyan leader and his family as well as other leaders of the Libyan regime, a comprehensive arms embargo and an immediate referral to the Hague-based International Criminal Court (ICC) for a crimes against humanity probe.

The prosecutor of the ICC on Monday announced a preliminary probe of possible crimes against humanity committed in Libya. The unrest in the country has killed at least 1,000 people and set off a "humanitarian emergency", the UN refugee agency UNHCR said, as almost 100,000 people, mostly migrant workers, fled the North African state.