David Cameron today said he was "optimistic" about Libya's future as Colonel Muammar Gaddafi issued a defiant warning to rebels that they faced a "long battle".
In a broadcast on Syrian TV, the deposed Libyan despot apparently vowed his forces would fight "in every street, every village and every city".
He said: "Let it be a long battle. We will fight from place to place, from city to city, from mountain to mountain.
"Let it be a long battle so that we can show to them that they cannot rule the Libyan people, they cannot subjugate our tribes."
World leaders were in Paris to meet members of Libya's National Transitional Council (NTC) at the "Friends of Libya" summit, chaired jointly by the Prime Minister and French President Nicolas Sarkozy.
The conference, attended by 60 international delegations, was set up to ensure the NTC has the full international support it needs.
Mr Cameron conceded there were still "huge challenges" in Libya making sure law and order prevails as well as ensuring Tripoli has sufficient water supplies.
But he insisted the "cynics and the armchair generals have been proved wrong" as hospitals and security services began to get back up and running.
Mr Cameron told US broadcaster CNN: "I'm an optimist about Libya.
"I've been an optimist all the way through and I'm optimistic about the National Transitional Council and what they are able to achieve.
"I think when you look at Tripoli today, yes, of course, there are huge challenges - getting water to that city, making sure there is law and order - but actually, so far, the cynics and the armchair generals have been proved wrong.
"The Libyan people have shown themselves very capable of actually getting their hospitals up and running, getting security back on the streets and we see police officers going back to work.
"It is still difficult, but there are very hopeful signs that this is a country with a leadership that wants to work and wants to come together, and they have been given that chance by what the international community, of Britain, France, and others, did, and I think it is very, very positive."
Mr Cameron also called on the International Criminal Court to take swift action to gather evidence of war crimes while it was still fresh.
He said: "We could see that there was going to be a slaughter - and when you see what Gaddafi has done elsewhere in his country, when you see the war crimes and the crimes against humanity he has clearly committed, I hope evidence will be being gathered by the ICC and others right now while that evidence is still fresh - we certainly avoided a massacre and a slaughter in Benghazi."
Diplomatic efforts to unlock Libyan assets are being stepped up to provide funds for the NTC, with the possibility of a new UN resolution on the frozen resources set to be discussed.
The first batch of almost £1 billion of Libyan dinar banknotes, which were seized after being printed in the UK, have already been sent to Libya after the UN sanctions committee agreed to a request from the British Government.
Around £140 million of newly-minted Libyan banknotes were transported to the Central Bank of Libya in Benghazi by the RAF.
They were part of a stock of 1.86 billion dinars (£950 million) printed in the UK, which were frozen under United Nations sanctions at the start of the crisis in Libya.