Libya announced another ceasefire tonight as the country braced itself for a second night's bombardment by allied forces.
The order - preceded by a barrage of anti-aircraft fire from the capital Tripoli - was issued in the name of the Libyan government and armed forces, rather than dictator Muammar Gaddafi.
A government spokesman in Tripoli said: "We, the Popular Social Leadership of Libya, recommend to the armed forces to announce an immediate ceasefire to all military units."
The announcement was followed by an order from the armed forces that the ceasefire would be effective from 9pm local time (7pm GMT).
A ceasefire announced by the Libyan government on Friday was apparently breached within a few hours.
UK forces took part in a devastating assault last night on Libya's air defences, which saw 112 Tomahawk missiles fired from US ships and a Royal Navy submarine, followed by a pre-dawn raid by RAF Tornados and US stealth bombers.
The Ministry of Defence declared itself "entirely comfortable" with the success of the raid, while US senior military officer Admiral Mike Mullen said that a no-fly zone was now effectively in place over the north African state.
US officials indicated that further operations would take place, and several RAF Typhoons arrived today from Coningsby in Lincolnshire to the Gioia del Colle airbase in southern Italy, to have easier access to targets in Libya.
Meanwhile, French sources said that four Qatari planes were joining its jets in patrolling the no-fly zone. The participation of the Arab state's forces would be a significant indication that the operation to enforce United Nations resolution 1973 is not simply a Western campaign, as Gaddafi has claimed.
There were signs of unease in the Arab world over the scale and nature of yesterday's attacks, which also included direct air strikes by French Mirage and Rafale jets on Gaddafi's tanks outside Benghazi.
The Arab League's Secretary General Amr Mussa appeared to suggest allied forces had gone beyond the measures to protect civilians called for by his organisation last weekend and authorised by Thursday's UN resolution.
"What has happened in Libya differs from the goal of imposing a no-fly zone," Mr Mussa was reported as saying.
"What we want is the protection of civilians and not bombing other civilians."
Responding to Mr Mussa's reported comments, a Foreign Office spokesman said: "Unlike Gaddafi, the coalition is not attacking civilians. The UN resolution authorises all necessary measures to protect the Libyan people.
"For the no-fly zone to be enforced safely, it is necessary to carry out carefully targeted operations against Libyan air defence capabilities.
"All missions are meticulously planned to ensure every care is taken to avoid civilian casualties. We will continue to work with our Arab partners to enforce the resolution for the good of the Libyan people."
Libyan state TV claimed that 48 civilians were killed and 150 wounded in last night's actions, which were denounced as terrorism by Gaddafi, who vowed to fight a long war "with unlimited patience and deep faith".
He said arms depots were being thrown open to arm the people to defend themselves against what state TV termed "the crusader enemy".
Meanwhile, Russia - which abstained in Thursday's Security Council vote - called on all involved in the Libyan conflict "to halt the indiscriminate use of force".
And Pope Benedict XVI used his regular Sunday blessing in the Vatican City to appeal "to those who have the political and military responsibility to take to heart the safety and security of citizens".
Some 15 French jets took to the skies over Libya today, but encountered no resistance from ground or air.
Prime Minister David Cameron was this evening chairing a meeting of the Government's Cobra emergencies committee in Downing Street.
The Tornado GR4s involved in last night's raid flew from RAF Marham in Norfolk on a 3,000-mile eight-hour round trip which required four in-flight refuellings and was the longest such mission since the Falklands War.
In a briefing at the MoD in London, Air Vice-Marshal Phil Osborn said: "We are entirely comfortable with the way last night's mission went in terms of success."
Allied forces had struck "high-value targets" in Tripoli and other parts of Libya, he said.
It is understood that the targets included radar early-warning stations and ground-to-air missile sites which had to be neutralised in order for the no-fly zone to be patrolled with minimum risk to allied planes.
Admiral Mullen, the chairman of the US Joint Chiefs of Staff, said that Gaddafi was no longer able to deploy helicopters and aircraft, meaning that "effectively the no-fly zone has been put in place".
Defence Secretary Liam Fox described last night's raids as "a success", and dismissed Libyan claims that civilian areas of Tripoli and Misrata had been hit.
Dr Fox told BBC1's The Politics Show: "All our targeting is done to absolutely minimise, as far as is humanly possible, casualties. I am not at all surprised that's what the regime is saying."
The Defence Secretary said he hoped that within a few days, one or more Arab states would be participating directly in the military action, while command and control of operations would be passed over from the US to Nato.
Dr Fox said: "I think it is very important for opinion in the Arab world to show that this is not simply the West acting, but this is the international coalition acting.
"To have active Arab participation in the no-fly zone makes it very clear on the Arab street that this is not about attacking the Arab world, this is to defend the Libyan people against a vicious and brutal dictatorship."
As international forces prepared a naval blockade of Libyan ports, Dr Fox said the Royal Navy warships HMS Westminster and HMS Cumberland were in the region ready to support operations.
Captain Karl Evans, Chief of Naval Staff, said the ships "remain poised to contribute to whatever form the embargo operation, probably led by Nato, will take off the coast off Libya".
Meanwhile, France's aircraft carrier Charles de Gaulle left the port of Toulon en route for a position off the Libyan coast.
Labour leader Ed Miliband supported the Government's action and paid tribute to "exceptionally brave and courageous" British forces.
Mr Miliband said: "The United Nations was right to act to uphold international values and law and to help the people of Libya in their hour of need.
"Britain and its Armed Forces were right to join in military action to support the will of the international community."
But the Campaign for Nuclear Disarmament (CND) condemned the attacks.
CND chairwoman Kate Hudson, speaking to around 100 protesters outside Downing Street, said: "We very much regret the decision of Britain and other countries to bomb Libya and we don't think the massive aerial bombardment is going to help bring about peace and democracy in Libya.
"The great danger now is that the situation will escalate and the bombardment from the West will increase support for Colonel Gaddafi."
As he left Downing Street after the Cobra meeting, the Chief of Defence Staff General Sir David Richards was asked what the emergencies committee made of the new ceasefire.
Gen Richards responded: "We are soaking it up. We are seeing what we can make of it."
Pentagon spokesman Vice-Admiral William Gortney said that a total of 124 Tomahawk missiles were eventually fired last night.
"We judge these strikes to have been very effective in significantly degrading the regime's capabilities," he said.
The ability of Gaddafi's forces to launch SA5, SA3 and SA2 surface-to-air missiles had been reduced.
Adm Gortney added: "There has been no new air activity by the regime.
"We have detected no radar emissions from the sites degraded and there has been a significant decrease in the use of all Libyan air surveillance radars."
And he said: "We are not ruling out further such missile strikes against valid targets if and when the need arises."
However he made clear that the Libyan dictator himself was not a target, telling a press briefing: "We are not going after Gaddafi.
"At this particular point I can guarantee he is not on the target list."
Adm Gortney said that US, British and French aircraft had attacked Gaddafi's ground forces on the outskirts of Benghazi last night.
"We judge this also to have been quite successful in halting the regime's ground movements in this region," he said. "Benghazi is not completely safe from attack but it is certainly under less threat than it was yesterday.
"We believe his forces are under great stress, suffering from isolation and a good deal of confusion."
Thanks to the success of last night's attacks, the coalition now has the capability to patrol Libyan airspace and would be shifting to a more consistent presence in the skies above the country, he said.
"The no-fly zone is now effectively in place," said Adm Gortney.
He confirmed that planes from Spain, Belgium, Denmark and Qatar had joined the coalition forces today, and said the US was working to hand over command and control within the next few days.
Asked about this evening's announcement of a ceasefire by Libyan authorities, Adm Gortney replied: "I question anything that Gaddafi calls for. He ordered troops to go into Benghazi after calling a ceasefire."Reuse content