Benghazi (Libya):  Libyan rebel chief Mustafa Abdel Jalil said on Saturday "the end is very near" for Moamer Gadhafi and that it will be "catastrophic," as insurgents pushing on the capital claimed to have seized a third key town in 24 hours.

"We have contacts with people from the inner circle of Gadhafi," said the chairman of the rebel National Transitional Council (NTC). "All evidence (shows) that the end is very near, with God's grace."

Abdel Jalil was speaking to reporters as a flurry of rumours suggested that Gadhafi was preparing to flee Libya.

"I expect a catastrophic end for him and his inner circle, and I expect that he will a create a situation within Tripoli. I hope my expectation is wrong," Abdel Jalil said.

"That would be a good thing that will end the bloodshed and help us avoid material costs. But I do not expect that he will do that," Abdel Jalil added.

Earlier, rebels claimed to have captured the strategic eastern oil hub of Brega, a day after saying they had seized two other key towns.

In another blow to Gadhafi, the rebels also said former premier Abdessalam Jalloud, who fell out of favour with the Libyan strongman in the mid-1990s but remains a highly popular figure, had defected and joined their ranks.

Jalloud "has gone to Benghazi on Friday night," rebel spokesman Juma Ibrahim said. "I don't know who he met there. He left by car," he added.

Overnight, rebel military commander Colonel Ahmed Omar Bani said that the ex-premier had managed to flee Tripoli and "has joined the rebels." Another source said his family accompanied him and they stopped first in Zintan.  His defection comes amid amid rumours that the Libyan strongman himself was preparing to flee as rebels appear to be closing in on the capital.

Jalloud was among the officers who grabbed power with Gadhafi in 1969 and was long considered the regime's second-in-command before being gradually sidelined in the 1990s.

Prime minister during the 1970s, he retired from politics following his dispute with Gadhafi and lived under hour arrest.

Libya's Awalam television channel quoted the former premier on its news ticker as saying: "Gadhafi's regime is finished."

On the ground, a top-ranking rebel official said of Brega, "the industrial zone is under our control; all Brega is now under our control."

On Friday they claimed the western refinery town of Zawiyah to be free, the last major barrier as they try to advance on Tripoli from the west.

The refinery is the only source of fuel to the capital, and could leave it without critical supplies.

Insurgents also said they seized Zliten from Gadhafi's forces, hours after saying they were in the town's centre, 150 kilometres (93 miles) east of Tripoli.

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

Meanwhile, a Tunisian defence official said Tunisian troops clashed with a group of armed Libyans overnight in the country's southwest.

(Agencies)