Libyan rebels advancing towards Sirte, the hometown of Moamer Gaddafi, were blocked Wednesday in the town of Bin Jawad as loyalists kept a stiff resistance, an insurgent commander said.

After taking Ras Lanuf, 150 kilometres (93 miles) west of Sirte, the rebels had advanced up to Bin Jawad, but were stuck there as they came under heavy artillery, rebel commander Fawzi Bukatif told AFP.

"Gaddafi’s forces are still fighting, we are surprised. We thought they would surrender with the fall of Tripoli," Bukatif said in the nearby coastal town of Zuwaytina, which also houses an oil exporting port.

"Maybe something or somebody is behind them," he said, adding "maybe" when asked if he was referring to Gaddafi or his sons.

"They built their defence lines on the 'Red Valley' ahead of Sirte. We are starting negotiations but they are blocked," he said without elaborating.

"It seems they will not surrender but we want to save the town and keep it as good as possible. We are trying to get free access to Sirte to establish a security committee there so our forces can guarantee that everything is in order. It is a question of time."

An AFP correspondent travelling with the rebels reported that heavy artillery fire could be heard from Gaddafi forces in Sirte.

Another rebel military representative in the rebel bastion of Benghazi said that freeing Sirte was just a "matter of time", adding that insurgents had captured Ras Lanuf.

"The retreat of the forces of the tyrant was possible after violent battles by the revolutionaries which removed the loyalists from Ras Lanuf," Ahmad Omar Bani said at a news conference.

He also said that Tripoli itself was fully liberated, although there were some snipers loyal to Gaddafi deployed.

Bani also said that it was "difficult" to comment on the location of Gaddafi himself.