Libyan rebels said they had severed the Gaddafi regime from its last remaining oil refinery yesterday, cutting off the pipeline from Zawiyah to Tripoli before launching a final assault on the plant itself.
Seizing the refinery would be a major symbolic victory for the rebels, as one of the vital assets around Zawiyah, a town that stands on the most important supply route connecting the remnants of the Gaddafi regime in Tripoli to the western border.
The attack was accompanied by further attacks to the south and west aimed at cutting off the capital's last connections to the outside world.
Despite the shutdown of the pipeline, there were reports that the refinery was still being protected by about 100 pro-Gaddafi fighters, among them snipers who took aim at approaching rebels.
After some regime loyalists surrendered at the weekend, those remaining locked refinery workers into the accompanying residential compound, hampering the rebels' freedom to attack, a rebel commander told the Associated Press. Theloss of the refinery would be a blow for Gaddafi, but its capacity has already been reduced by two thirds, largely because the flow of crude to the plant has been drastically cut.
Fuel oil supplies are less critical a loss to the regime than petrol brought to Tripoli by road, mostly from Tunisia.
Yesterday saw fierce fighting in Surman, as regime forces tried an outflanking manoeuvre to gain a firm grip on Zawiyah. A rebel spokesman said Gaddafi loyalists retreated from Tiji and Badr "because they felt surrounded from all sides." He added: "I think they will surrender soon because the roads to Tripoli are closed."
Rebel forces did not have it all their own way. The Tripoli troops shelled Zawiyah, driving opposition forces out of the centre and from some southern areas of the town.
Nato air strikes appear to have taken place in a bid to stop the heavy artillery, with prolonged bombings in the north of the town. Rebel commanders claim they will control all of Zawiyah and be in a position to launch an assault on Tripoli in three days time.
Opposition military leader, Nabil Rahimi, said they had hoped to attack yesterday, the anniversary of the 17 February revolution.
"We are just going to be a few days but it is important to wait for our reinforcements and supplies," he said. "We are facing more resistance than we thought from the Khamis Brigade. The very fact that they have been sent shows that Gaddafi is now desperate," he added.
The unit named after Khamis, one of the Libyan leaders' sons, has the reputation of being one of the better trained and equipped forces.
Negotiations for a ceasefire held in the Tunisian city of Djerba, and the capital Tunis, ended with rebel and regime participants saying "some progress" had been made.
Both sides have apparently agreed they must do everything to avoid a bloodbath when the opposition launch an assault on Tripoli. But yesterday, rebel spokesman Abdulrahman denied his side had been engaged in those talks.