"Security sources have told us that the Lebanese army has managed to penetrate a few hundred metres into the camp," Zheina Khodr, Al Jazeera's correspondent outside the camp near Tripoli, said.

"The Lebanese army has said in a statement that its soldiers are working to clean out pockets from where Fatah al-Islam armed fighters are operating."

Barrages of artillery shells and mortar bombs landed inside the Palestinian refugee camp on Saturday, levelling its two highest buildings and reducing others to smoking ruins.

Military helicopters fired two rockets and machinegun barrages at targets on the camp's coastal side amid the constant thud of explosions.

"Since yesterday morning, the shelling has been ongoing all over the camp. Two shells fell on the building I'm in now. Several buildings have collapsed," a Palestinian resident inside the camp said.

"There's only one clinic with one doctor left. There's no electricity, bread or medicine."

'Casualties mounting'

Jihad Omar, who is working with rescue teams in the centre of the camp, said that casualties were mounting and that wounded people were lying in the streets.

He said shelling continued in the centre of the camp where there were no Fatah al-Islam fighters, only civilians.

The army has urged refugees still trapped inside the camp to "be patient and to expel those criminals from among you".

Lebanese soldiers stake out the Nahr al-Bared camp as part of a continuing siege [AFP]

Siniora said that the camp's population had fallen from more than 31,000 to fewer than 3,000, including the fighters, after civilians fled after the outbreak of fighting on May 20.
  
He accused Fatah al-Islam of preventing the remaining civilians from leaving the camp in an apparent bid to use them as human shields.

Security sources said six soldiers had been killed in the last two days, bringing the death toll in the two-week conflict to 106, of whom 41 are soldiers.

At least 16 people were killed inside the camp on Friday, but it was unclear whether they were Fatah al-Islam fighters or civilians.

A delegation of Palestinian clerics has appealed for a truce to transport the wounded to hospitals and bury the dead.