In Libya, heavy fighting has forced the shutdown of one of its biggest refineries.

The refinery is on the edge of the flashpoint town of Zawiyah, 50 km west of Tripoli, a refinery official confirmed today.

“Heavy weapons have been fired nearby and we can’t run the refinery under these conditions,” the official said.

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Libya’s Zawiyah refinery is the biggest provider of gasoline for cars in the violence-gripped country, and has a total capacity of 120,000 barrels per day.

The refinery has been operating at 70 percent capacity for the past two weeks.

The refinery official said he planned to open the site later today, but it was not clear whether it would be possible.

Any sustained shutdowns at the refinery in the city of 250,000 could add to instability in Libya as government forces try to crush rebels determined to topple the country’s leader Muammar Gaddafi.

Zawiyah was briefly described as a rebel stronghold in the uprising, which erupted against Gaddafi on February 15.

Meanwhile, the Daily Mail is reporting that three private jets owned by Colonel Gaddafi have left Libya heading for three different countries.

Greek officials said they spotted the Libyan Airlines Falcon 900 jet as it briefly entered airspace for around 15 minutes earlier today.

And Al Jazeera reported that there are three private planes understood to have taken off from a military airstrip near Tripoli.

Karl Stango-Navarra, a journalist based in Valletta, Malta, told Al Jazeera that the three jets are flying in three different directions.

“One is suggested to be Vienna, the other is supposed to be Athens in Greece, and the other is Cairo, Egypt,” Stango-Navarra said.

“Obviously, nobody knows who may be aboard the planes,” he said.

The development comes as revolutionary forces which have established the Libyan National Council gave Gaddafi 72 hours to quit and leave the North African country amidst escalating violence.