By Mohammed Abbas and Maria Golovnina
BIN JAWAD/TRIPOLI, Libya (Reuters) - Libyan rebels advanced from the east on Muammar Gaddafi's hometown Sirte and clung to positions in a western town near the capital Tripoli after withstanding two armored assaults by government forces.
Intense, sustained machinegun fire rattled the center of Tripoli, Gaddafi's biggest stronghold, before dawn on Sunday. It was unclear who was shooting or what had caused it. Witnesses also heard much wild honking of car horns.
Calm settled back over the western town of Zawiyah after nightfall, with rifle-toting insurgents on rooftops and manning checkpoints on streets leading into the center. But the rebels said they were bracing for another tank and artillery attack by government on Sunday.
A doctor in Zawiyah, some 50 km (30 miles) west of Tripoli, said at least 30 people, mostly civilians, were killed during fighting on 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, on the heels of seizing the oil port of Ras Lanuf, and were thrusting westwards toward Sirte 160 km (100 miles) away.
Exultant after asserting control over much of the east of the vast oil-exporting North African state in a two-week-old insurrection against 41 years of rule by the maverick autocrat Gaddafi, some rebels said an assault on Sirte was imminent.
"We're going to attack Sirte, now," rebel fighter Mohamed Salim told Reuters, while another fighter, Mohamed Fathi, said: "Listen, we have no organization and no military plan. We go where we're needed."
"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.
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.
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 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 if the insurrection in Libya, inspired by revolts that toppled despots in nearby Egypt and Tunisia, succeeded.
"There would be Islamic jihad in front of you, in the Mediterranean," he said. "(Osama) bin Laden's people would come to impose ransoms on land and sea. We will go back to the time of Red Beard, of pirates, Ottomans imposing ransoms on boats."
Gaddafi 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.
In Benghazi, eastern heartland of the insurrection, the opposition National Libyan Council said it had named a three-member crisis committee, including a head of military affairs and foreign affairs. Its head told Al Jazeera television it expected to be formally recognised soon by some countries.
In Tripoli, Deputy Foreign Minister Khaled Kaim told reporters Zawiyah was "quiet and peaceful" late on Saturday. "We hope by tomorrow morning life will be back to normal."
In Zawiyah, whose takeover by rebels earlier last week shook the Libyan leader because Libya's west has traditionally been Gaddafi's basis of popular support, residents said sporadic clashes after dusk abated by late evening.
But the atmosphere was tense with the situation seeming fluid and the rebels were on alert for a fresh barrage.
Abu Akeel, a Zawiyah resident, told Reuters government forces had shelled houses and fired on a mosque where people were taking shelter. Another resident said he saw more than 20 tanks advance across the main square during the second assault.
In Bin Jawad, rebels played the pre-Gaddafi monarchist national anthem over a loudspeaker. Government fighter jets and a helicopter circled overhead but did not open fire.
The Libyan revolt is the bloodiest yet in a string of uprisings against long-entrenched rulers in the Middle East and North Africa over the past two months.
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.
(Additional reporting by Michael Georgy in Tripoli, Alexander Dziadosz in Ajdabiya, Mohammed Abbas in Bin Jawad, Stefano Ambrogi in London, Nick Vinocur in Paris and Tom Pfeiffer in Benghazi; Writing by Mark Heinrich; Editing by Miral Fahmy)