International powers gathered in London on Tuesday to map out Libya's future as support grew behind the idea of Muammer Gaddafi going into exile.

British Foreign Secretary William Hague called for Gaddafi to face the International Criminal Court but refused to rule out the possibility of offering the Libyan leader a safe corridor out of the country.

Hague's comments came amid reports that a possible exile plan could be discussed at the meeting of more than 35 countries.

"We're not in control, of course, of where he might go. I'm not going to choose Colonel Gaddafi's retirement home," Hague told BBC radio.

"Of course I believe he should face the court, people who have committed crimes, if the prosecutor has the information on them, should be before the International Criminal Court," he said.

"But of course where he goes, if he goes, is up to him and the people of Libya to determine and we will not necessarily be in control of that."

More than 40 delegations, including seven Arab states and the Arab League, are gathering in London after sweeping advances by rebel forces under cover of Western air strikes have been halted by government forces near Gaddafi's birthplace, Sirte.

The leaders of Britain, France, Germany and the United States agreed in a video-conference Monday that the London talks should aid 'the political transition in Libya'.

Ahead of the meeting, US Secretary of State Hillary Clinton met a leading member of the Libyan opposition in London, a senior administration official said.

It was her second meeting with Mahmud Jibril, who handles foreign affairs for Libya's Provisional Transitional National Council, following a first on March 15 in Paris where Clinton was attending a Group of Eight meeting.

Earlier on Tuesday, Hague also met with Jibril, who Britain have invited to London but not to the conference.

Hague said the transitional council was 'an important and legitimate political interlocutor', but stressed Britain was committed to strengthening its contacts 'with a wide range of members of the Libyan opposition who are working to create a Libya where the legitimate aspirations of its people can be met'.

In another sign of growing Western links with the rebels, a US envoy will travel to the rebel stronghold of Benghazi 'sometime soon' to establish a 'systematic channel' with groups seeking to oust Gaddafi, a US official said.

France is the only Western country to have officially recognised the rebels.

Qatar followed suit on Monday.

The West decided at a meeting in Paris on March 19 to authorise military action in support of UN Security Council Resolution 1973, which called for citizens to be protected from pro-regime forces and a no-fly zone to be implemented.

Ten days later, hundreds of strikes on Gaddafi's tanks and armoured cars have transformed the opposition campaign, allowing rebels to push westwards from their stronghold of Benghazi and gain control of a string of towns.

NATO finally agreed on Sunday to take over full command of military operations in Libya from a US-led coalition, resolving an issue which has dogged international thinking.

While France, Britain and the United States have driven forward the military action on Libya, they have been determined to ensure Arab nations are seen to be supporting their efforts.

Iraq, Jordan, the United Arab Emirates, Lebanon, Qatar, Tunisia and Morocco will all be represented in London, as well as the Arab League.

But Russia, whose Foreign Minister Sergei Lavrov has criticised the West's military action, saying it goes beyond the terms of the Security Council resolution, said it had not been invited.