NAHR AL-BARED, Lebanon - The Lebanese defense ministry on Tuesday reiterated its call for Islamist militants besieged in a Palestinian refugee camp to surrender, calling their 12-week battle with the army suicidal.

The appeal came as army helicopters attacked bunkers of Fatah al-Islam fighters holed up in Nahr al-Bared camp, located near the northern port of Tripoli.

"The court system is the quickest way to end the current situation and wasting time and refusing to heed the army's call to surrender and be fairly judged is suicidal and you alone bear responsibility," the ministry said in its appeal.

It also urged the Al-Qaeda-inspired fighters to allow some 100 women and children thought to be still inside the camp to leave.

"Let the women and children decide their own fate because holding them is a crime before God and the law," the statement said.

An AFP correspondent earlier watched four helicopters each open fire twice on the tiny sector in the south of the camp where the Islamists have been holding out since May 20.

The air raids were the second in two days and were accompanied by firing from Islamist and army positions.

Army commander in chief General Michel Sleimane estimates that only 70 Fatah al-Islam fighters are left in the camp, dug in to subterranean shelters that the military is trying to break through.

He said the group was planning attacks both in Lebanon and abroad when the army moved in.

"It's a well-trained organisation, equipped with sophisticated arms, including heavy weapons, experienced in handling explosives," he said.

"They have around 100 women and children with them who refuse to leave the camp despite our appeals and different attempts to mediate."

The shadowy Islamic extremist group has denied charges that it is linked to Osama bin Laden's Al-Qaeda, but has admitted that it shares ideological ties with the network.

The Palestinian camps in Lebanon, built from 1948 when thousands fled the newly created Jewish state, have been fortified over the years to make them able to withstand Israeli air raids.

But a Lebanese army spokesman told AFP: "These (helicopter) bombardments are very effective. Several shelters have been partly destroyed, but the soldiers have to shift the debris and disarm explosives before they can enter them."

Most of the 31,000 refugees for whom the camp was home fled at the start of the fighting which began on May 20 and which has killed more than 200 people, including 136 soldiers. It is not known how many Islamists have died.

On Monday, the United States, which accuses Syria of trying to destabilise Lebanon and regain influence there, designated Fatah al-Islam a "terrorist" group. Damascus has denied any links with the group.

The US statement said Fatah al-Islam, an offshoot of the Syrian-backed secular Palestinian militant group Fatah al-Intifada, initiated hostilities in Nahr al-Bared camp with an "unprovoked attack" on Lebanese security forces. -AFP