ZAWIYA, Libya — Dozens of opposition fighters surrounded Libya's last functioning oil refinery Wednesday and laid siege to about 100 government troops, part of a push which brought them closer to seizing this strategic western city.
A rebel victory in Zawiya could be a turning point in the 6-month-old war and leave Moammar Gadhafi nearly cornered in his increasingly isolated stronghold of Tripoli, the capital, just 30 miles to the east along the Mediterranean coast.
Rebel fighters are now closing in on the capital from the west and the south, while NATO controls the seas to the north. The opposition is in control of most of the eastern half of the country and has declared Benghazi, 620 miles east of Tripoli, as its de facto capital.
Wednesday's fighting focused around the sprawling refinery complex on the western outskirts of Zawiya, a city of 200,000. The rebels, who began their assault on the refinery a day earlier, took control of the facility's three-story administration building, tearing down the Gadhafi regime's green flag that flew over the grounds.
Desperate Gadhafi troops cut off from the main government forces took cover in a residential compound and closed the gates to prevent workers from fleeing, rebels said. The troops barricaded themselves in and positioned snipers on rooftops. An Associated Press photographer inside the refinery with rebel troops heard occasional bursts of gunfire.
The Libyan rebels made a dramatic advance on Saturday out of their bases in the western mountains near Tunisia into Zawiya on the Mediterranean coast. Since then, they have taken control of 70 percent of the city, rebel commanders say, and have been slowly gaining ground in fierce battles with Gadhafi's forces.
A rebel field commander in Zawiya, Osama Arusi, said the clashes at the refinery shut down an oil pipeline to Tripoli, where a third of Libya's 6 million people live. Analysts said neither a pipeline shutdown nor a capture of the 120,000 barrel-per-day refinery in Zawiya would have a major impact on Gadhafi's ability to secure fuel.
The flow of crude to the refinery from fields in southwest Libya had mostly halted since midsummer. The refinery was believed to be running at about one-third of its normal capacity, drawing mainly on crude that was in its storage tanks. Zawiya produces mostly fuel oil, not gasoline, which Gadhafi had trucked in mainly from Tunisia and, to a lesser extent, Algeria.