MANILA - FIGHTING has escalated in the southern Philippines as troops step up the hunt for an Italian Red Cross engineer held by an Islamic rebel group for five months, a marine spokesman said on Sunday.

Six rebels belonging to the Abu Sayyaf, a militant group with ties to regional network Jemaah Islamiah (JI), were killed in clashes on southern Jolo island, Lieutenant-Colonel Edgard Arevalo told reporters. Five rebels were wounded, he added.

On Saturday, the rebels killed six soldiers and wounded 17 in an attack on a military convoy returning to a base in Parang town on Jolo, two days after security forces raided a rebel base in nearby Indanan, killing eight rebels and two soldiers.

'Our troops will not stop until we have neutralised the Abu Sayyaf and resolved the kidnapping problem in the south,' Lt-Col Arevalo said, adding the Italian Red Cross engineer, Eugenio Vagni, was being kept far from the conflict areas.

'Based on all the information that we're getting, Vagni is alive. He was sighted by some civilians taking a bath in a river near Parang three days ago. We have information that he was not near the conflict areas in Indanan and Parang.'

The government has offered a reward of 500,000 pesos (S$15,208) for information on the whereabouts of Mr Vagni, 61, the last of three workers from the International Committee of the Red Cross (ICRC) held on Jolo.

Mr Vagni was kidnapped, along with Swiss Andreas Notter and Filipina Mary Jean Lacaba, by Abu Sayyaf rebels while inspecting a sanitation project at a local prison on Jolo on Jan 15.

Mr Notter walked to freedom on April 18 while Ms Lacaba was freed on April 2. Ransoms are believed to have been paid. Mr Vagni, believed to be suffering from a hernia, has difficulty moving around but was able to call his wife on June 2, the ICRC said on June 11 on its website.

At least 22 people have been killed and dozens wounded in the last three days of fighting on Jolo island, an Abu Sayyaf stronghold in the south of the mainly Roman Catholic state. -- REUTERS