The Lebanese army increased the pressure Saturday on al-Qaeda-linked militants barricaded in a Palestinian refugee camp near Tripoli.

Military helicopters joined dozens of army tanks and armoured vehicles pounding the Nahr el-Bared camp.

"The Lebanese army was shelling at a very steady rate. We could hear machine-gun fire and see a number of explosions over the horizon," the CBC's Nahlah Ayed reported from outside the camp.

The onslaught forced Fatah Islam fighters to abandon some of their positions.

Local reports said both sides had been considering calling a humanitarian ceasefire to allow civilians a chance to escape the fighting. Instead, the fighting continued.

"At the time the ceasefire was supposed to begin, the fighting was as intense as it has been this past couple of days," Ayed said.

A Lebanese army soldier from a navy commando unit flashes a V sign to colleagues atop an armoured personnel carrier as they replace another unit at the Palestinian refugee camp Nahr el-Bared during clashes in Tripoli on Saturday.
(Hussein Malla/Associated Press)

The government has vowed to crush the militants, although an all-out assault on the camp would risk sparking violence elsewhere in the country.

"Some people talking from inside the camp to outside media say that the camp has largely been destroyed," Ayed reported.

"We've also heard that there have been casualties on both sides, and likely among civilians."

Three more soldiers died in fighting on Saturday, bringing the army's death toll to five with 15 others wounded.

Lebanese soldiers take new positions: reports

On Friday, dozens of Lebanese army tanks and soldiers began pounding the camp. Eighteen people had been killed by the evening.

At least 50 armoured carriers and tanks massed at the northern edge of the camp and encircled it, in an attempt to trap the militants.

There were also unconfirmed reports that Lebanese soldiers had taken over control of new positions on the edge of the camp to snipe at members of Fatah Islam.

Thousands of Palestinians have fled the camp, but thousands more remain inside. Fatah Islam claims to have more than 500 fighters in the camp, armed with automatic weapons, mortars and rocket-propelled grenades.

Sporadic gunfire exchanges have continued daily since a truce halted three days of heavy fighting at the beginning of the siege.

Across Lebanon, about 400,000 Palestinian refugees live in refugee camps, many of which are rife with armed groups.