Jolo operation: Tactics and equipment

Estrada (left) has said the operation will be over in days

BBC News Online's Tarik Kafala

In the words of Philippine President Joseph Estrada, the current military campaign against the Abu Sayyaf will leave the rebels "pulverised to ashes".

After months of humiliation at the hands of Abu Sayyaf, who seemed able to take hostages and demand ransoms at will, the government clearly wants to destroy the rebels in a short, sharp operation.

An alleged Abu Sayyaf fighter captured by the army

Reports from the region suggest that the offensive is unlikely to be over in a matter of days, as the Philippine army has suggested, in part because of the tactics employed by the army.

The news blackout imposed on Jolo means that a clear picture of the operation is hard to build, but reports suggest that the Philippine military is not directly engaging the rebels on the ground.

Philippines operation

4,000 troops deployed in Jolo campaign

Helicopters and bomber jets used

Mortar and artillery attacks on rebel targets

Campaign started on 16 September

BBC South-East Asia Correspondent Simon Ingram reports from the southern Philippine town of Zamboanga that clashes between rebels and army are much more sporadic than reports have previously suggested.

This, he suggests, means that Mr Estrada's initial claims that the operation should be over within a week now looks extremely optimistic.

The Philippine army is depending mainly on aerial attack from air force bombers and helicopters, as well as mortar and artillery shelling.

Paul Beaver of Jane's Defence Weekly says this "hands off" approach to a jungle counter insurgency operation is unlikely to work.

"To do this at long range is reminiscent of Vietnam, and we all know what happened there," Mr Beaver told the BBC.

Retreat

Reports have suggested that the Abu Sayyaf rebels have retreated into Jolo's mountainous jungle interior or have left the island altogether.

Abu Sayyaf

Backed by Iran and Libya and groups in Pakistan and Sudan

Armed with AK47 rifles, machine guns, grenade launchers and mortars

Command structure: independent cells under a single leader

(Source: Jane's Defence Weekly)

Transportation and telephone links to the island have been cut by the military. Cellular telephone masts have also been shut down because the rebels were using mobile phones to communicate.

The Abu Sayyaf are believed to be retreating in high-powered speedboats bought with more than $15m in ransom reportedly received from Libya and Malaysia for freeing hostages.

Libya maintains that the ransom money is going only into development programs for Jolo and nearby islands, but there are indications that the payments have gone to swelling and re-equipping the Abu Sayyaf.

Abu Sayyaf boosted

Before the series of kidnappings began in March, the Abu Sayyaf had fewer than 200 armed men and about 1000 members. The number is believed to have grown to more than 3,000 after the ransom payments.

According to a report in Jane's Defence Weekly, the Abu Sayyaf are organised into small independent cells which come under the leadership of a single overall commander. The Abu Sayyaf include fighters with experience in Afghanistan.

The rebels receive backing from Libya and Iran, and radical Islamic groups in Sudan and Pakistan.

Before the recent hostage taking, the rebels were armed with AK47 rifles and handguns.

Since then, the rebels are believed to have acquired heavy machine guns, mortars and grenade launchers.