Britain has begun taking political action against Muammar Gaddafi's regime, after evacuating the "vast majority" of British nationals from Libya.
Three further rescue missions evacuating a total of around 150 British nationals from "multiple locations" in the eastern Libyan desert were confirmed by defence secretary Liam Fox on Sunday evening.
The rescue missions came after foreign secretary William Hague called on Col Gaddafi to step down.
But concerns about the situation on the ground continued to mount as the flood of refugees fleeing Libya across the Tunisian border sparked fears of a developing humanitarian crisis.
Britain took its first decisive political steps against the Gaddafi regime on Sunday by freezing the colonel's assets and those of his daughter and four sons.
"We have throughout these crises in Egypt and Tunisia... been careful to say it's the people of these countries who must own the solution, but the people of Libya have risen up against Colonel Gaddafi," Mr Hague told BBC1's The Andrew Marr Show.
"We have here a country descending in to civil war with atrocious scenes of killing of protestors and a government actually making war on its own people so of course it is time for Colonel Gaddafi to go. That is the best hope for Libya."
The export of uncirculated Libyan currency from the UK has been banned and diplomatic immunity has been suspended for all members of the Gaddafi regime, preventing them from entering Britain.
"I decided to implement this UN resolution in the UK as quickly as possible, before the financial markets reopened," chancellor George Osborne said on Sunday evening.
"Together with the action taken by William Hague and Vince Cable, this is a strong message for the Libyan regime that violence against its own people is not acceptable."
The measures mean that, from 17:15 on Sunday, all funds, financial assets and economic resources owned or controlled by the listed individuals and entities, or by anyone acting on their behalf or by entities controlled by them, were frozen, the Foreign Office said.
The UK financial sector has been informed that funds or other economic resources cannot be made available to them or their entities. The Treasury will monitor compliance "rigorously".
Prime minister David Cameron said on Sunday evening: "All this sends a very clear message to this regime: it is time for Col Gaddafi to go and to go now. There is no future for Libya that includes him."
The moves followed a UN security council resolution tabled by Britain and France which was unanimously adopted on Saturday.
The resolution called on the Libyan government to meet its responsibility to protect its population, immediately end all human rights violations, stop any attacks against civilians, and respect the popular will, aspirations and demands of its people.
Navi Pillay, the UN's high commissioner for human rights, said: "Although reports are still patchy and hard to verify, one thing is painfully clear: in brazen and continuing breach of international law, the crackdown in Libya of peaceful demonstrations is escalating alarmingly with reported mass killings, arbitrary arrests, detention and torture of protestors."
Britain waited until after over 150 UK oil workers were evacuated from desert camps south of Benghazi before commencing its diplomatic offensive.
The Foreign Office said the "vast majority" of Britons in Libya at the start of the violence had left the country and that only a "small residue" remained.
"I'm sure everyone will be relieved; good work has been done today and I want to pay tribute to our brave armed forces personnel who carried it out," Mr Cameron added.
"It is risky and it is difficult but I judged it was the right thing to do because there are British citizens spread out across those oil platforms particularly in the eastern desert area in Libya.
"We need to get those people home, we need to do so safely, we can do so helping other nationalities at the same time."
The last charter flight from Tripoli airport arrived at Gatwick airport on Saturday night carrying around 100 passengers, 58 of whom were British.
HMS Cumberland departed Benghazi for Malta carrying around 200 civilians, roughly 50 of which were British. A charter flight departed from Valletta for Gatwick at 15:00 carrying 148 passengers, 79 of which were British nationals.
Shadow foreign secretary Douglas Alexander said the government needed to do all it could to help the remaining Brits trapped in Libya.
"I am calling on David Cameron to come to the House of Commons on Monday, not just to explain why the Foreign Office got its evacuation plan so badly wrong at the start but how Britain can be a leader and not a follower in the efforts to increase the pressure on Gaddafi to stand down," he said.
"We strongly support the revoking of diplomatic immunity for Gaddafi and his family. It is time for Gaddafi to listen to the will of his people and go."
The individuals whose assets have been frozen are Colonel Muammar Abu Minyar al-Gaddafi, Aisha Muammar Gaddafi, Hannibal Muammar Gaddafi, Khamis Muammar Gaddafi, Mutassim Gaddafi and Saif al-Islam Gaddafi.
Tens of thousands of people are leaving Libya through the Tunisian and Egyptian borders, prompting the Department for International Development to dispatch teams to the two neighbouring countries.
"Reports from humanitarian experts in Eastern Libya indicate that food and medical supplies are available with markets open," the Foreign Office said.
"We remain very concerned about the humanitarian implications of the situation and are following developments closely."