Guerrillas of Algeria's Islamic Salvation Army (AIS) have begun emerging from their hideouts as the deadline for a government amnesty passes.

President Abdelaziz Bouteflika had given the Islamists until midnight on Thursday to surrender or face a "merciless" campaign to eradicate them.

The news agency AFP says nine commanders of the AIS, the military wing of the outlawed Islamic Salvation Front (FIS), have come down from the highlands over Jijel to negotiate the demobilisation of about 1,000 fighters in the area.

The FIS urged President Bouteflika to release its leaders and other jailed members as the six-month amnesty period expired.

The rebels are reported to have said it could take up to two weeks for all their fighters to come down from the mountains.

A BBC correspondent in North Africa says it now seems likely that the deadline will be at least informally extended.

The deadline, which passed without incident, is part of President Bouteflika's plan to end the Islamic insurgency that has left more than 100,000 dead.

The FIS formally dissolved its military wing earlier this week.

But the rebel group blamed for most civilian killings, the GIA, has so far rejected the government's offer of a partial amnesty in return for giving up its weapons.

Government troops have been deployed in preparation to root out those who do not comply.

Reports say thousands of soldiers, including paratroopers, have arrived in Jijel, a coastal city east of Algiers, whose surrounding area is considered one of the main areas of rebel activity.

Artillery pieces and scores of helicopter gunships have been sighted in nearby mountainous areas, and warships are stationed off the coast.

Large-scale military activity has also been seen in the Tizi-Ouzou, Boumerdes and Ain Defla regions.

Opposition split

Algeria erupted in violence in 1992 when the government annulled a general election which the FIS was poised to win.

President Bouteflika's peace move offers amnesty, with a probation period, to rebels who have not killed, bombed or raped.

For those who have committed such crimes, the maximum sentence is set at 20 years.

Algerian politicians say the GIA and another group, the Da'wa wal Djihad, will be targeted when the amnesty period finishes.

The two groups have been accused of killing more than 600 people since the start of the amnesty last July.

They want Algeria to become an Islamic state that would follow Sharia law.

It is not clear if AIS fighters will take part in any anti-rebel operation, but its leader has repeatedly said his 8,000 men are ready to join the army in the fight against the radicals.

Since the AIS declared a truce in October 1997, its forces have largely remained in their barracks.