Two soldiers and six members of an Islamic militant group holding an Italian Red Cross hostage were killed in heavy fighting in the southern Philippines on Thursday, the military said.
There was no immediate confirmation on the physical state of Eugenio Vagni, the 62-year-old Italian who was abducted by the Abu Sayyaf along with two other aid workers -- who have since been released, unharmed -- nearly five months ago.
A marine combat patrol came upon about 150 heavily armed Abu Sayyaf members near the town of Indanan on southern Jolo Island at dawn, the military said.
"A fierce firefight ensued and is still ongoing," Navy spokesman Lieutenant Colonel Edgard Arevalo said.
Two soldiers and six militants were killed, and four soldiers were wounded, he said.
He said the Abu Sayyaf unit was led by Albader Parad and Abu Pula, two senior commanders of the group thought to be holding Vagni.
The Swiss and Philippine colleagues of the International Committee of the Red Cross (ICRC) staffer were released separately in April.
Interior Secretary Ronaldo Puno last week said Vagni was alive, but said that weeks in the harsh tropical jungle was taking its toll on the captive, who was known to be suffering from a hernia.
Puno had said that efforts to recover Vagni were being slowed by landmines planted by the Abu Sayyaf.
Foreign militants believed to be from the Jemaah Islamiyah (JI) regional extremist network were aiding the Abu Sayyaf kidnappers, making it more difficult for negotiators to resolve the crisis peacefully, Puno had said.
Arevalo on Thursday said reports from the field indicated Indonesian JI member Umar Patek was helping the Abu Sayyaf.
Patek and compatriot Dulmatin are wanted for the 2002 bombings in Bali, Indonesia that killed more than 200 people, many of them tourists.
The Philippine military had reported that Dulmatin was killed in the southern Philippines last year, but Indonesian authorities later said forensic tests were inconclusive.
The US government has offered a million dollars for the capture of Patek, and 10 million dollars for Dulmatin.
The Abu Sayyaf is a small group of Islamic rebels blamed for the worst militant attacks in the Philippines.
It once received funding from Osama bin Laden's Al-Qaeda network when it was first organised by young Afghan-trained firebrand Abdurajak Abubakar Janjalani, according to local and international intelligence and security groups.
His death in a clash with police in 1998 led to a power vacuum within the Abu Sayyaf, which has since specialised in kidnappings and bombings.