BIN JAWWAD, Libya // Rebel forces laid siege to Muammar Qaddafi's hometown and stronghold of Sirte, the gateway to the capital, Tripoli, as Western and Arab nations prepared to meet in London on Tuesday to seek an exit for Libya's long time leader.
Ban Ki-moon, the UN secretary general, Hillary Clinton, the US secretary of state, the Arab League, the African Union and around 40 foreign ministers were scheduled to join the talks, seeking to ratchet up pressure on Col Qaddafi.
Italy's foreign minister, Franco Frattini, said several nations planned to put forward a deal which would propose a ceasefire, exile for Col Qaddafi and a framework for talks, between Libya's tribal leaders and opposition figures, on the country's future.
No representative from Libya's opposition was expected to attend the conference, but an official familiar with planning for the talks said an envoy was expected to travel to London to meet with British diplomats on the sidelines. The official demanded anonymity to discuss the meeting with the opposition envoy ahead of a formal announcement.
Thanks to international air strikes that begun on March 19, Libya's rebels are in a much stronger position than a week ago, having recaptured all the territory lost earlier to Col Qaddafi forces, including two key oil terminals.
But the rebels remain woefully outgunned by Col Qaddafi forces and it is unclear how they can take the stronghold of Sirte without further aggressive international air support. Attacks on Monday were repelled by heavy mortar and rocket fire.
Rebels acknowledged they could not have taken so much ground without the air and cruise missile strikes. Libya state television reported new Nato air strikes after nightfall, targeting "military and civilian targets" in the cities of Garyan and Mizda.
Nato insisted that it was seeking only to protect civilians and not to give air cover to an opposition march. But that line looked set to become even more blurred. The air strikes now are clearly enabling rebels bent on overthrowing Col Qaddafi to push towards the final line of defence on the road to the capital.
The rebels are currently just 100 kilometres from Sirte, the bastion of Col Qaddafi power in the centre of the country, beyond which is the largely rebel-held city of Misrata - and then the capital.
Sirte could therefore see some of the fiercest fighting of the rebellion, which began on February 15.
Some residents were fleeing Sirte, as soldiers from a brigade commanded by Col Qaddafi son al-Saadi and allied militiamen streamed to positions on the city's outskirts to defend it, witnesses said.
The city is dominated by members of the Libyan leader's Gadhadhfa tribe. But many in another large Sirte tribe - the Firjan - are believed to resent his rule, and rebels are hoping to encourage them and other tribes there to help them.
Fighting in such a densely populated area is likely to complicate the rebels' advance and add to the ambiguity of the Nato-led campaign, authorised by a Security Council resolution to take all necessary measures to protect civilians.
