Manila  - Four Muslim militants were killed Sunday in a clash with government troops on a southern Philippine island where the rebels are holding captive an Italian Red Cross worker, the military said.

Major General Juancho Sabban, commander of a military anti-terrorism task force, said the firefight erupted when troops caught up with about 100 Abu Sayyaf rebels in Parang town on Jolo island, 1,000 kilometres south of Manila.

Sabban said the rebels were sleeping when soldiers opened fire at them in the village of Danapa.

"The confirmed enemy death is four but we believe there were more," he said, adding that two soldiers suffered minor injuries.

Sabban said the rebels, led by Abu Sayyaf commanders Albader Parad and Umbra Jumdail, were not with their hostage, Italian Red Cross volunteer Eugenio Vagni, 62.

"Vagni was in a separate area," he said. "We have a separate effort to locate him."

Vagni was abducted with two other Red Cross workers on January 15 after visiting the Jolo provincial jail to oversee a water and sanitation project. His two colleagues - a Swiss national and a Filipino - were freed separately in April.

The Abu Sayyaf has been blamed for some of the worst terrorist attacks in the Philippines. It has also been behind a number of high-profile kidnappings in the country, mostly involving foreign hostages. (dpa)