Manila  - Philippine troops have "slowed down" operations against Muslim militants holding captive three staff of the International Committee of the Red Cross (ICRC) to pave the way for negotiations, a military spokesman said Sunday.

Brigadier General Gaudencio Pangilinan, the armed forces' civil relations chief and spokesman for the ICRC hostage crisis, said government soldiers have been told to maintain their positions while the negotiations are ongoing.

"It was a collective decision because negotiations are ongoing," he said. "But there will be no stop in the operations, it's just a slowdown. Before we were closing in on the kidnappers. Now troops were told to just occupy the vantage position."

The ICRC staff - Swiss Andreas Notter, Italian Eugenio Vagni and Filipino Mary Jean Lacaba - have been in captivity on Jolo island, 1,000 kilometres south of Manila, for one month now.

They were abducted by al-Qaeda-linked Abu Sayyaf rebels on January 15 after visiting the provincial jail on Jolo to oversee a water and sanitation project.

Pangilinan said the military will not ease its cordon around the kidnappers during the negotiations.

"The pressure is still on," he said. "We will not release the pressure until something comes out of the negotiations. We do not want clashes to occur and endanger the hostages. If there will be peaceful or non-violent resolution, why not?"

In the nearby province of Basilan, police blamed the Abu Sayyaf for the kidnapping of a Sri Lankan peace advocate last Friday.

Umar Jaleel, 36, was seized from the headquarters of the Belgium-based NGO Global Nonviolent Peaceforce in Lamitan City in Basilan, 900 kilometres south of Manila, on February 13.

Basilan provincial police chief Salik Macapantar said initial investigation showed the nine suspects who abducted Jaleel were under an Abu Sayyaf commander named Furiji Indama.

He said police officers and soldiers have been dispatched to track down the rebels.

The Abu Sayyaf has been blamed for some of the worst terrorist attacks in the Philippines as well as high-profile kidnappings involving foreigners.

In 2000, the Abu Sayyaf abducted 21 European tourists and Asian workers from a Malaysian resort island and brought them to Jolo. The hostages were ransomed off for millions of dollars before they were freed months later.

The following year, a separate band of Abu Sayyaf rebels seized 17 Filipino vacationers and three American tourists from a western Philippine resort. Most of the hostages were later rescued or ransomed off, but two of the Americans were killed. dpa