Heavy automatic weapons fire erupted in the Libyan capital Tripoli Sunday, the first such outbreak in Muammar Gaddafi''s main stronghold in a two-week-old insurrection against his 41-year-old rule.

Government spokesman Mussa Ibrahim denied any fighting was under way in Tripoli, saying the gunfire was staged to fete the army''s recapture of several cities from rebel forces.

It was unclear who was doing the shooting, which started just before daybreak, or what had caused it. Machine gun volleys, some of them heavy caliber, reverberated around central Tripoli along with ambulance sirens, pro-Gaddafi chants, and a cacophony of car horns as vehicles sped through the vicinity.

"These are celebrations because government forces have taken control of all areas to Benghazi and are in the process of taking control of Benghazi," Ibrahim said, referring to Libya''s rebel-controlled second largest city situated in the far east.

State television reported that government forces had retaken the important coastal cities of Zawiyah and Misrata, to the immediate west and east of Tripoli, and were also heading for Benghazi, where the opposition National Libyan Council has set up a crisis committee, in a quest for foreign recognition.

The state television report provided no details and, with poor communication affecting all areas outside Tripoli, there was no immediate way to confirm the battlefield turnaround. Rebel spokesmen could not be reached for comment.

"I assure you..., there is no fighting going on in Tripoli. Everything is safe. Tripoli is 100 percent under control. What you are hearing is celebratory fireworks. People are in the streets, dancing in the square," said Ibrahim, adding, however: "I would like to advise not to go there for your safety."

Deputy Foreign Minister Khaled Kaim had told reporters late Saturday that Zawiyah was "quiet and peaceful. "We hope by tomorrow morning life will be back to normal."

Libya''s insurrection was inspired by generally peaceful uprisings that toppled despots in neighboring Egypt and Tunisia and that have spread to other Arab nations with entrenched leaders and a deficit of democracy, good governance and jobs.

Advance on sirte

As of Saturday night, Libyan rebels were advancing from the east on Gaddafi''s hometown Sirte, around 500 km (300 miles) from Tripoli, and dug into positions in Zawiyah after withstanding two armored assaults by government forces.

A tense calm settled over the western town of Zawiyah after nightfall Saturday, with rifle-toting insurgents on rooftops and manning checkpoints on streets leading into the center.

Before the state television report that Zawiyah had changed hands, the rebels said they were bracing for another tank and artillery attack by government forces Sunday.

A doctor in Zawiyah, some 50 km (30 miles) west of Tripoli, said at least 30 people, mostly civilians, were killed during fighting Saturday that wrecked the town center, raising to at least 60 the death toll from two days of battles.

Almost 600 km (400 miles) to the east along Libya''s Mediterranean coast, insurgents said they took the town of Bin Jawad Saturday, on the heels of seizing the oil port of Ras Lanuf, and were thrusting westwards toward Sirte.

Exultant after asserting control over much of the east of the vast oil-exporting North African state in a revolt against the flamboyant autocrat Gaddafi, some rebels said an assault on Sirte was imminent.

"If (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," said Peter Zeihan, analyst with the U.S.-based Stratfor intelligence newsletter.

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.

Gaddafi redoubt

Where many eastern towns have fallen with scant resistance, Sirte is unlikely to be a pushover. It has long received hefty subsidies from Gaddafi, who liked to host Arab and other international conferences in the coastal city.

Sirte also hosts a major air base and significant military forces loyal to Gaddafi and the Sirte basin is home to a large part of Libya''s oil reserves.

Britain''s Sunday Times reported that rebels had seized a British SAS special forces unit of up to eight soldiers escorting a junior diplomat in eastern Libya on a secret diplomatic mission to make contact with opposition leaders.

The SAS intervention apparently angered opposition figures who fear Gaddafi could use any evidence of Western military intervention to sway patriotic support away from the uprising, according to the London paper.

In a French newspaper interview, Gaddafi said he was embroiled in a fight against Islamist terrorism and expressed dismay at the absence of support from abroad.

"I am surprised that nobody understands that this is a fight against terrorism," Gaddafi told le Journal du Dimanche.

"Our security services cooperate. We have helped you a lot these past few years. So why is it that when we are in a fight against terrorism here in Libya no one helps us in return?"

Western leaders have denounced what they call Gaddafi''s brutal response to the uprising, and the International Criminal Court said he and his inner circle face investigation for alleged targeting of civilians by his security forces.

Gaddafi said Islamic holy war would engulf the Mediterranean region if the insurrection succeeded.

He added that his government was "doing well" despite the turmoil and warned Europe against an influx of Libyan migrants to its shores if his foes drove him from power.

Unclear rebel leadership

But the opposition, while assembling an inspired fighting force, has failed to produce a convincingly clear leadership, a weakness Gaddafi hopes to exploit as the struggle continues.

The International Energy Agency said the revolt had blocked about 60 percent of Libya''s 1.6 million bpd (barrels per day) oil output. The drop, due largely to the flight of thousands of foreign oil workers, will batter the economy and have already jacked up crude prices abroad.

Exultant after asserting control over much of the east of the vast oil-exporting North African state in a revolt against the flamboyant autocrat Gaddafi, some rebels said an assault on Sirte was imminent.

"If (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," said Peter Zeihan, analyst with the U.S.-based Stratfor intelligence newsletter.

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.