Pete Norman, Sky News Online
Heavy gunfire has shattered the pre-dawn calm in the Libyan capital Tripoli as rebel groups advanced on Colonel Muammar Gaddafi's hometown of Sirte.
The intense gunfire, which included machine gun, semi-automatic and tracer fire, was unleashed in the heart of Tripoli.
"This has been the most intense gun fire we have heard in Tripoli in the week we have been here," Sky News foreign correspondent Lisa Holland, reporting for the capital, said.
The gun fire was interspersed with the honking of car horns and cheering but a government spokesman denied fighting was under way in Tripoli.
"I assure you, I assure you, I assure you, I assure you, there is no fighting going on in Tripoli," Mussa Ibrahim, a government spokesman, said.
"In their minds they have been talking repeatedly, the regime has been telling us there is confidence in Colonel Gaddafi," Holland said.
Meanwhile 30 miles to the west of Tripoli, calm has settled back over the town of Zawiyahafter nightfall on Saturday, with rifle-toting insurgents on rooftops and manning checkpoints on streets leading into the centre.
But the rebels said they were bracing for another tank and artillery attack by government troops today after withstanding two armoured assaults by government forces earlier on the weekend.
A doctor in Zawiyah said at least 30 people, mostly civilians, were killed during fighting on Saturday that wrecked the town centre, raising to at least 60 the death toll from two days of battles.
Almost 400 miles to the east along Libya's Mediterranean coast, insurgents said they took the town of Bin Jawad, on the heels of seizing the oil port of Ras Lanuf, and were thrusting westwards towards Sirte 100 miles away.
However Libyan TV has since claimed government forces have retaken Ras Lanuf and the town of Misratah.
Enbolden by success in the two-week-old insurrection against 41 years of rule by the dictator Muammar Gaddafi, some rebels said an assault on Sirte was now imminent.
"We're going to attack Sirte, now," rebel fighter Mohamed Salim said.
Another fighter, Mohamed Fathi, said: "Listen, we have no organisation and no military plan. We go where we're needed."
"IfBenghazi, (rebels) can expand down into the Gulf of Sirte... they've got a very good shot at independence at the least - or maybe even overturning him at the most," analyst Peter Zeihan said.
But others were wary of the limitations of an undisciplined rebel force made up of soldiers who have bolted from Gaddafi's ranks and volunteers who have more enthusiasm than experience.
Destruction of a huge ammunition dump has also thwarted some rebels in their plans for revolt.