At least three people have been killed and up to 50 injured after the army opened fire on protesters in the Libyan city of Zawiyah.
Video: Sky News' Alex Crawford reports from Zawiyah.
The attack happened during a demonstration involving several thousand people, most of whom were unarmed, who were calling for Colonel Muammar Gaddafi to quit.
The western port city, which is about 30 miles from the capital Tripoli, is currently surrounded by the dictator's security forces.
As the anti-government protesters made their way towards the military lines on the outskirts of the city, the army opened fire.
Many people ran way, fleeing and shouting, and they were shot as they ran away.
There were then frantic calls for ambulances. The vehicles were shot at as they arrived at the scene.
The injuries are all at the head, neck and chest. There is a feeling that there was a deliberate attempt to kill the protesters, not to frighten them.
There did not seem to be much firing over the heads of the protesters, or any attempt to scare them away.
The army was shooting to kill them and the victims' injuries have reflected that.
Earlier in the day, at least 10 anti-regime fighters were reportedly killed as the leader's forces tried to regain control of the city.
A rebel told Sky News that opposition forces were surrounded on all sides.
The unnamed man said: "Gaddafi's troops have entered now and they've heavily attacked us. Ten of our people have died."
He said there were at least 200 troops, some of whom were armed with rocket-propelled grenades.
He added: "We're surrounded from all sides. We can't move anywhere. We're fighting until the last man standing."
His comments were echoed by ex-justice minister Mustafa Abdel Jalil, the head of Libya's rebel National Libyan Council, who vowed: "Victory or death."
He told crowds in Al Bayda: "We are people who fight, we don't surrender. Victory or death. We will not stop till we liberate all this country.
"The time of hypocrisy is over. Gaddafi must go."
Another resident in Zawiyah said an estimated 2,000 troops had positioned themselves to the south of the city with 80 armoured vehicles headed there from the east.