Manila  - Six soldiers were wounded Friday in a landmine explosion on a southern Philippine island where Muslim militants are still holding captive two foreign Red Cross staff, a navy spokesman said.

The explosion occurred after a military truck loaded with marines hit a landmine in Patikul town on Jolo island, 1,000 kilometres south of Manila, according to Lieutenant Colonel Edgard Arevalo.

Arevalo said all the injured soldiers suffered shrapnel wounds and were being treated at a military hospital in Jolo.

Arevalo said the attack could have been perpetrated by the al-Qaeda-linked Muslim Abu Sayyaf rebels, who late Thursday released one of the three hostages after 78 days in captivity.

Filipino Mary Jean Lacaba was released unharmed Thursday evening to Vice Governor Lady Anne Sahidullah, who is also the head of the local Red Cross on Jolo.

Two other companions of Lacaba, Swiss Andreas Notter and Italian Eugenio Vagni, were still being held by the Abu Sayyaf rebels.

The three were seized by Abu Sayyaf guerrillas on January 15, shortly after visiting the Sulu provincial jail where they inspected a water and sanitation project.

President Gloria Macapagal Arroyo expressed hope that the rebels would soon release the two other captives. (dpa)