Coalition forces have launched a new wave of airstrikes on western and central Libya after rebels were blocked from entering Colonel Muammar Gaddafi's home town of Sirte.
News of the bombings came as the UK and France urged loyalists in the country to abandon the regime and ahead of a conference on the conflict in London tomorrow.
Rebel advances west towards the capital Tripoli had been halted by Libyan government forces following a series of explosions in Sirte.
It had been claimed the town had fallen to the opposition.
But Sky's Andrew Wilson spoke to rebels who said they had met strong resistance outside the town.
A joint statement from British Prime Minister David Cameron and French president Nicolas Sarkozy urged Gaddafi to step down immediately.
"We call on all his followers to leave him before it is too late," they said.
Mr Cameron also said RAF pilots had notched up more than 120 sorties and 250 flying hours so far as part of international military action to protect Libyan civilians.
And a British miltary spokesman said RAF Tornados destroyed two pro-Gaddafi tanks and two armoured vehicles near Misratah.
A military official on Libyan TV claimed coalition forces have hit civilian areas.
But US authorities insisted there had been no confirmed reports of civilian deaths from the airstrike and said allied forces were not supporting the rebels.
They also released footage from an aircraft carrier of Tomahawk missiles being fired on targets in Libya - of which they said there had been 199 so far.
t came after the rebels took five key towns - Ajdabiyah, Brega, Uqayla, Ras Lanuf and Bin Jawad - as coalition airstrikes allowed them to move west over the weekend.
Earlier, a rebel spokesman claimed that the coastal town - 280 miles east of Tripoli - had fallen.
But foreign journalists inside Sirte said there was no sign the opposition was in control.
Sky's Emma Hurd, in the rebel-held city of Benghazi, said: "Rather strangely the government decided to take a few journalists there yesterday and they stayed there overnight.
"They are telling us that the town has not fallen to the rebels. They are saying it is quiet there ... there is certainly no evidence that the rebels are inside Sirte and in control of that town."
A Reuters reporter said he had seen police and soldiers in the centre of Sirte and had not witnessed any fighting.
However, it was also reported that that a convoy of 20 military vehicles, including truck-mounted anti-aircraft guns, had been seen leaving Sirte and moving westwards towards Tripoli as the rebels closed in.
Dozens of civilian cars carrying families and personal belongings were also reportedly leaving the town.
Libyan television confirmed that Sirte had been the target of air raids.
Witnesses in the capital said the strikes targeted the road to the airport, as well as the eastern Ain Zara neighbourhood.
Tripoli and the desert town of Sabha were also reportedly hit by coalition aircraft, with the Libyan government saying there had been a number of civilian casualties.
Sky News producer Tom Rayner, reporting from Tripoli, said: "We heard at least four explosions, about 30 seconds apart."
The Ministry of Defence said RAF Tornados flying from Britain had taken part in the raid on Sabha, which targeted ammunition bunkers.
"Initial reports suggest that the bunkers have been destroyed and that the Libyan government has been denied ammunition it uses to threaten civilians in the north of the country," it said in a statement.
State television blamed "the colonial aggressor" for the airstrikes.
Meanwhile, Libya's state news agency said a ceasefire had been announced in the battle with "terrorists" in Misratah.
"The city of Misratah now enjoys security and tranquility and public services have started to recover their ability to provide customary services to all citizens," the Jana news agency quoted the foreign ministry as saying.