Libya: Protests hit Gaddafi stronghold of Tripoli
Libyan security forces have used tear gas to disperse hundreds of protesters after Friday prayers in Col Gaddafi's stronghold of Tripoli.
A BBC reporter in the eastern suburb of Tajoura said demonstrators had burnt the official Libyan flag.
Secret police had tightened security in the area earlier, and Gaddafi loyalists set up traffic checkpoints.
Clashes also erupted in the town of Zawiya and the oil port of Ras Lanuf, with heavy casualties reported.
Reports from Ras Lanuf described the sound of multiple explosions and heavy artillery on the outskirts of the port. Opposition fighters had reportedly advanced on the city. Pro-Gaddafi forces withdrew to Ras Lanuf two days ago after a battle.
Rebels later said they had seized the airport at Ras Lanuf, while state television reported that the town of Zawiya had been retaken by pro-Gaddafi forces. There was no independent confirmation of either claim.
The Libyan revolt, which broke out in mid-February to end Col Gaddafi's 41-year rule, had appeared to have reached deadlock.
The BBC's Wyre Davies in Tajoura says the protesters were calling for the fall of the Gaddafi government when suddenly police opened fire with dozens of tear gas canisters and baton rounds.
The atmosphere had been tense earlier, as noon prayers began in Tajoura's main mosque, while secret police milled around outside.
There was also a heavy military presence on main roads around the district, where Gaddafi loyalists have been searching cars at checkpoints.
There were unconfirmed reports of mosques having been closed and arrests overnight, while internet services appeared to have been cut off.
The authorities stopped some foreign journalists leaving the main media hotel in Tripoli, saying it was to protect them from "al-Qaeda elements".
Reporters were later told they could leave the hotel on condition they boarded official buses to government-selected locations.
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.
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
- Gaddafi forces carried out the second air raid in as many days on the nearby key rebel-held harbour of Brega, home to the country's second-largest oil facility, Al Arabiya news network reported
- Interpol issued an "orange alert" relating to Col Gaddafi and 15 other Libyans, saying it would help member states enforce sanctions against them
- The European Union's humanitarian aid commissioner demanded that Libya allow help into the country, citing increasing concerns over the situation of refugees in border areas, AFP reported
The opposition - a mixture of citizen militias and army defectors armed with machine guns and rocket-propelled grenades - have also been securing Brega in anticipation of a fresh onslaught by Gaddafi loyalists.
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.
The major western rebel-held cities of Zawiya and Misrata have also repelled attacks by Gaddafi loyalists.
The leader of the opposition National Libyan Council reportedly told cheering crowds in Libya's second city of Benghazi 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."
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.
An estimated 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.