Thousands of troops have been deployed in potential trouble spots in Algeria, ahead of the expiry of a government amnesty for Islamist rebels.

President Abdelaziz Bouteflika has promised a merciless war against those who refuse to surrender themselves and their weapons by midnight.

Residents and security officials say a big assault is now planned to root out those who do not comply.

Reports say thousands of soldiers, including paratroopers, have landed in one of the main areas of rebel activity - the coastal city of Jijel, 220km (137 miles) east of Algiers.

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

About 100,000 people are said to have been killed in Algeria since 1992, when the government annulled a general election in which an Islamic party had taken a commanding lead.

The most militant group, the Armed Islamic Group (GIA), has refused the amnesty offer. It is blamed by the government for most of the estimated 100,000 deaths since the Islamist insurgency began.

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.

Another group, the Islamic Salvation Front (FIS), dissolved its military wing, the AIS, on Tuesday after a blanket amnesty was announced for its members.

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.

The FIS was the group set to win the 1992 election that the military cancelled, sparking the cycle of violence.

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

For those who had killed, raped or bombed, the maximum sentence was to be 20 years.

Mr Bouteflika, who came to power in April in a controversial presidential election, has said he is determined to bring peace to Algeria