• Clashes as demonstrators gather in Tajura area of Tripoli • Gaddafi forces attack rebel town of Zawiyah in west • Opposition forces fight for eastern town of Ras Lanuf

This article is more than 9 years old

This article is more than 9 years old

Security forces have used teargas and live ammunition to disperse hundreds of anti-government protesters who marched in Tripoli after Friday prayers, as Muammar Gaddafi's regime launched a fightback on several fronts.

Several hundred demonstrators gathered in Tajura, an area east of the capital, chanting: "Gaddafi is the enemy of God."

West of the capital, security forces loyal to Gaddafi launched an offensive to retake Zawiyah, which had passed into rebel hands, and residents said 30 civilians had been killed. The town's rebel commander was said to be among the dead.

In the east, rebels attacked the oil town of Ras Lanuf, which lies on a strategic coastal road, claiming to have taken its airport.

The rebellion in Zawiyah – the closest opposition-held territory to the capital – has been an embarassment to the authorities who are trying to show they control at least the west of the country.

In the town, which is about 50km (30 miles) west of Tripoli, pro-Gaddafi forces fought for hours with rebels who have been holding the town centre, according to Reuters.

A local man called Ibrahim told Reuters: "From 11am until now Gaddafi's mercenaries, mainly from Africa, have been opening fire on people here. Hundreds of victims are now in the town hospital."

A brigade led by one of Gaddafi's sons was reported to have attacked Zawiyah. A resident said the troops from the Khamis brigade, named after Gaddafi's son, attacked Zawiyah's western side, firing mortars and then using heavy machine guns and automatic weapons to fight armed residents and allied army units.

"Our men are fighting back the force, which is big," the resident told Associated Press.

Zawiyah has beaten back several assaults in the past week in what is turning into a military stalemate. Gaddafi's forces have been unable to take back significant ground while his opponents, ragtag citizen militias backed by mutinous army units, lack the resources to take Tripoli.

In Tripoli, several hundred demonstrators gathered in Tajura, chanting: "Gaddafi is the enemy of God."

Protesters tore down posters of the Libyan leader and spraypainted walls with graffiti reading: "Down with Gaddafi" and "Tajura will dig your grave."

Scores of police cars descended on the area, forcing journalists from the scene, and at least one person was detained.

Soon after the march began, officers fired teargas at the crowd. The protesters scattered, but quickly regrouped before security forces fired live ammunition, scattering the protesters again. It was not immediately clear if the shots had been fired in the air or at the marchers.

"I am not afraid," one marcher told Associated Press. The 29-year-old said one of his relatives had been shot dead in protests a week ago – not by militias, but by a pro-Gaddafi infiltrator at the demonstrations. "There are many spies among us. But we want to show the world that we are not afraid," he said, speaking on condition of anonymity because of fears of retaliation.

Earlier, security officials set up checkpoints in Tripoli backed by tanks and armoured personnel carriers. The checkpoints blocking many of the routes into Tajura, where demonstrations took place last week, were manned by well-trained forces who subjected vehicles to thorough searches.

Officials tried to stop foreign journalists leaving their hotel in Tripoli, claiming it was for their protection, but later allowed them out, although they were not permitted to go to Tajura.

The opposition called for protesters to march out of mosques after noon prayers in demonstrations against Gaddafi, who has vowed to fight to the "last man and bullet". In protests last Friday, pro-regime militiamen opened fire immediately on the marchers, killing and wounding a still unknown number. Since then, Gaddafi forces have seized suspected dissidents in night raids. Bodies of people who disappeared have been left in the street and militiamen have searched hospitals for the wounded to take away.

Opponents of the regime said they had been expecting government forces to respond violently to the latest marches.

"We do not have any weapons. We will go to the mosque and then say Gaddafi should leave," Mohammed, a Tajura resident, told Reuters. "They [pro-Gaddafi militias] will attack."

In the east, rebel forces moved on the oil terminal of Ras Lanuf, 400 miles east of the capital.

"We're going to take it all, Ras Lanuf, Tripoli," one of the rebels, Magdi Mohammed, told Reuters. The rebels were attacking a military base on the outskirts of the port. The army responded with artillery fire and helicopters firing machineguns.

Rebels said they had captured the airport and intended to push forward towards the military base after dark.

Meanwhile, the head of Libya's rebel national Libyan council has vowed to fight to victory or death.

"We are people who fight, we don't surrender," Mustafa Abdel Jalil, the former justice minister, told cheering crowds in al-Bayda in the rebel-held east of the country. "Victory or death. We will not stop till we liberate all this country … The time of hypocrisy is over."