Libya conflict: UN agreement sought to unfreeze assets
Foreign Secretary William Hague has said it may take time to negotiate a United Nations resolution to release frozen Libyan assets.
Mr Hague said UK, French and US diplomats were trying to get agreement from Russia and China - both of whom have a UN Security Council veto.
He said it was "important for the world to come together".
Russia and China both refused to endorse the UN resolution allowing Nato's military intervention in Libya.
The UK government's National Security Council met for the fourth consecutive day on Thursday.
Meanwhile, in Libya, rebels are continuing to fight running battles with pro-Gaddafi forces in Tripoli, while Col Gaddafi himself remains on the run.
The opposition political authority, the National Transitional Council (NTC), has put a $1.7m (£1m) bounty on his head.
Billions of pounds of Libyan assets - including £12bn in London alone - have been frozen in recent months to prevent them being used by the Gaddafi regime.
The US, UK and France want to unfreeze them to provide funds for the NTC and for humanitarian efforts.
A draft resolution proposing such a move is expected to be presented to the UN Security Council later, but Mr Hague said work was needed to persuade Russia and China to agree to it.
He said the two countries had abstained when the UN resolutions allowing air strikes on Libya were passed in March and acknowledged that they had "sometimes been critical of the implementation of those".
But he said: "I think they have to recognise that there has been a fundamental change in the situation.
"That what has happened in Tripoli over recent days means that it is important for the world to come together in supporting a future for the Libyan people.
"Now that is something that should be supported by the UN security council but this will take some negotiation. It will take some time. I can't say yet when it will be possible to pass such a resolution."
Deputy Prime Minister Nick Clegg said the time needed for negotiations with Russia and China was "a little frustrating".
"But, of course, as we all know there are some countries who had their doubts about Nato's role, who are now less willing to move very quickly as Libya emerges into a new condition," he added.
African Union role
The UN sanctions committee released $500m of frozen Libyan assets on Wednesday night following a request by the US.
South Africa agreed to the move on the condition the money would be used for humanitarian purposes, but blocked the release of a further $1bn for the NTC itself.
The South African ambassador to the UN said approving the $1bn would imply official recognition of the NTC as Libya's legitimate rulers - which neither his country nor the African Union had done.
A Downing Street spokeswoman said Prime Minister David Cameron - who is on holiday in Cornwall - had spoken to South African President Jacob Zuma on Thursday morning.
"They agreed that Libya now has the opportunity for transition to a peaceful, democratic and inclusive government and they discussed how the international community should actively and urgently support this process," she said.
"The prime minister welcomed South African support of the release of $500m of frozen Libyan assets for humanitarian needs, and the leaders agreed that the African Union needs to take swift decisions at their summit in Addis Ababa today on the unfreezing of further assets."
Defence Secretary Liam Fox said South Africa's apparent stalling was "disappointing" and there was "a huge moral pressure" on the country's leadership to "stand with the Libyan people".
The $1.5bn is only a fraction of the total Libyan assets held by the US and European Union, and South Africa has no power to veto a wider UN-backed release.
Col Gaddafi was one of the main founders of the African Union and its key financial backer. He has used his big oil revenues to establish a network of political and financial relationships on the continent.
Mr Fox said Nato was providing intelligence and reconnaissance support to help track down Col Gaddafi, along with the other remnants of his regime.
A Nato spokesman, however, insisted the organisation did not target specific individuals.
Mr Fox also declined to comment on a report in the Daily Telegraph that British special forces are on the ground and helping with the hunt.
He said British military advisers remained in Libya, helping the rebels with "communications, logistics, the chain of command and so on", but he again insisted there were "absolutely no plans to have any British boots on the ground".
He also said UK troops continued to take part in Nato missions in Libya and had been "more active" on Wednesday than on previous nights in attacking "the resisting elements of the regime".
Mr Hague said the Gaddafi was "finished", but there was a danger that forces loyal to him would keep fighting for some time.