At least eight people have been killed in heavy fighting in the southern Philippines, the military has said.
Two soldiers and six members of a group holding an Italian Red Cross hostage were said to be killed on Thursday.
There was no immediate confirmation on the physical state of Eugenio Vagni, the 62-year-old Italian who was abducted by the Abu Sayyaf group nearly five months ago.
A marine combat patrol came upon about 150 heavily armed Abu Sayyaf fighters near the town of Indanan on southern Jolo island at dawn, the military said.
"A fierce firefight ensued and is still ongoing," Lieutenant Colonel Edgard Arevalo, a navy spokesman, told AFP news agency.
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.
Two other aid workers seized along with Vagni were released separately in April.
Health concern
Ronaldo Puno, the interior secretary, said last week that Vagni was alive, but many weeks in the harsh tropical jungle was taking its toll, as he is said to be suffering from a hernia.
Puno also said that efforts to recover Vagni were being slowed by landmines planted by the Abu Sayyaf fighters.
PHOTO CAPTION
Map locates Indanan, Philippines, where troops clashed with Abu Sayyaf fighters.
Al-Jazeera