"Zawiyah is free," Libya rebels said Friday as they took up positions in its hospital hours after pounding the centre of this oil refinery town, the last major barrier as they try to advance on Tripoli from the west. The key refinery is the only source of fuel to the capital, and could leave it without critical supplies.

Hundreds of rebels armed with assault rifles had marched from the central square, a stronghold of forces loyal to Muamer Gaddafi, to the hospital decorated with portraits of the veteran leader, an AFP journalist said.

Gaddafi snipers were staked out on rooftops as the battles raged, with buildings and streets in the town centre showing signs of massive damage from the warfare.

Rebels have been seeking to sever Tripoli's supply lines from Tunisia to the west and to Gaddafi's hometown of Sirte in the east in a move they hope will cut off the capital, prompt defections and spark an uprising inside Tripoli.

Insurgents also said they seized Zliten from Gaddafi's forces, hours after saying they were in the town's centre, 150 kilometres (93 miles) east of Tripoli. "Zliten is now under the control of our fighters, but the fighting is not finished," the Information Centre For Misrata Military Council said, adding that 40-50 Gaddafi forces were dead and 12 African mercenaries captured.

Rebel forces also claimed that former Libyan prime minister Abdessalam Jalloud, who fell out of favour with Gaddafi in the mid-1990s, had joined them, but they declined to provide his location "for security reasons."

A senior rebel said Jalloud and his family had arrived in Zintan, a rebel-held town southwest of the capital, while rebel television channel Libya Awalam quoted Jalloud on its news ticker as saying: "Gaddafi's regime is finished." On Saturday Jalloud was said to be in the rebel headquarters of Benghazi.

"He has gone to Benghazi yesterday night (Friday). I don't know who he met there. He left by car," said rebel spokesman Juma Ibrahim speaking in Zintan.

Jalloud was a member of the officers who grabbed power with Kadhafi in 1969 and was long considered the regime's second-in-command before being gradually sidelined in 1990s. He served as prime minister from 1972 to 1977. He was prime minister from 1972 to 1977.

Jalloud -- who has remained a popular figure in Libya -- had retired from politics following his dispute with Gaddafi and lived under hour arrest. His defection was the latest blow to the regime of Kadhafi and comes amid rumours that the Libyan strongman himself was preparing to flee.

With the rebels vowing to take Tripoli before the Muslim holy fasting month of Ramadan ends in late August, Italian Foreign Minister Franco Frattini urged the population of the capital to rise up against Gaddafi.

"We hope the people of Tripoli... understand the regime has harmed its own people and will therefore join a process of political change to cut off room for manoeuvre for Gaddafi's regime," Frattini said.

Meanwhile, the International Organisation for Migration said it was drawing up plans for the evacuation of thousands of migrants stranded in Tripoli because exit points have been cut off after a spate of rebel successes.

"There are already thousands of Egyptians who are ready for evacuation now, and what we are hearing is that every day there are more and more requests," said IOM spokeswoman Jemini Pandya said.

For its part, the International Committee of the Red Cross said the intensified fighting has seen a "rapid deterioration in the humanitarian situation" in several Libyan towns.
"We are hearing about hospitals being attacked or used for military purposes," the ICRC said, saying conditions for civilians were deteriorating in Brega, the western towns of Zawiyah, Garyan, and Sabratha.

Meanwhile NATO, in its operational update for Friday, said it had hit targets in the vicinity of Tripoli, Zawiyah and Zliten, including nine military facilities around the capital.
Reports from Brasilia also said that clashes broke out late Friday at the Libyan embassy in the Brazilian capital between supporters of Kadhafi and his opponents.

Advocacy group Human Rights Watch meanwhile announced in a statement it had sent a "four-person team" to Tripoli and others sites in western Libya under government control where "they engaged senior Libyan officials on human rights in the conflict and visited sites of NATO airstrikes where civilians are alleged to have died."