Libya unrest: Deadly clashes in battle for Zawiya Published duration 4 March 2011

media caption Jeremy Bowen reports from Tajura near Tripoli, where one anti-government protester spoke about people's fears of being killed

A fierce battle has been raging in the key Libyan city of Zawiya, after loyalist forces launched an operation to retake it from rebels, reports say.

Heavy casualties are reported, with one witness telling Reuters news agency up to 50 people were dead.

Fierce fighting was also reported in the oil port of Ras Lanuf, while in the capital, Tripoli, security forces fired tear gas to disperse protesters.

Rebels aiming to end Col Gaddafi's 41-year rule still hold other areas.

Dead and injured

Reports from Zawiya, about 30 miles (50 km) west of Tripoli, said the most senior rebel commander in the city was among those killed.

One resident told BBC Arabic TV that many people had died when a peaceful demonstration came under fire.

A second Reuters witness said he had just come from the hospital and many people were lying dead and injured.

"We have counted 30 dead civilians," he said. "The hospital was full. They could not find space for the casualties."

Libyan state television said the town had been retaken by pro-Gaddafi forces, although later reports spoke of "pockets of resistance".

Reports from the eastern port of Ras Lanuf meanwhile described the sound of multiple explosions and heavy artillery. Opposition fighters had reportedly advanced on the city. Pro-Gaddafi forces withdrew to Ras Lanuf two days ago after a battle.

Rebels at Ras Lanuf later told news agencies they had taken complete control of the town, but there was no independent confirmation.

There were also conflicting reports about the situation in Brega. Some government sources said the town was in rebel hands, while others insisted it was not.

In Tripoli, the BBC's Wyre Davies in the suburb of Tajoura said security forces fired dozens of canisters of tear gas and baton rounds at protesters who had gathered on the streets after Friday prayers.

Secret police had tightened security in the area earlier, and Gaddafi loyalists set up traffic checkpoints.

image caption Fierce fighting has been reported around several key locations, including the port of Ras Lanuf

Protests last week after Friday prayers in several districts of the city ended in bloodshed when government forces fired on civilians, witnesses have said.

Pro-Gaddafi militias have been roaming Tripoli in civilian cars, according to residents.

A wave of detentions, killings and disappearances has been reported in the city in recent days, and bodies of missing people have reportedly been left in the street.

In other developments:

A Libyan warplane bombed the rebel-held Mediterranean port town of Ajdabiya, narrowly missing a munitions dump

Several hundred mercenaries from the Tuareg community in the north African country of Mali have just joined government forces, a senior Malian official told the BBC

Interpol issued an "orange alert" relating to Col Gaddafi and 15 other Libyans, saying it would help member states enforce sanctions against them

image caption Protests after Friday prayers in Tripoli were quelled with tear gas and baton rounds

Libya's second city, Benghazi, remains in rebel hands. The leader of the opposition National Libyan Council reportedly told cheering crowds in the city they would not give up.

"We are people who fight, we don't surrender," former Libyan Justice Minister Mustafa Abdel-Jalil, who went over to the opposition last month, was quoted as saying by Reuters news agency.

"Victory or death. We will not stop till we liberate all this country."

Later a large explosion was heard at an arms dump outside Benghazi. More than a dozen people are reported to have died, with many more injured. Hospital sources say the blast was accidental, not caused by an air strike.

The UN refugee agency UNHCR has expressed new concern that people trying to flee into Tunisia may be finding their way blocked by armed pro-government forces, after a sudden drop in the numbers crossing the border.

At least 10,000 people a day were crossing the border earlier in the week, but the number suddenly fell to fewer than 2,000 on Thursday, the agency says.

"Many of those who have crossed the border appear to be frightened and are unwilling to speak," UNHCR spokeswoman Melissa Fleming.

"We believe that has implications - that they may have been intimidated in some way."

Tens of thousands of people, most of them migrant workers, have streamed to the border since the unrest began, sparking a humanitarian crisis.