Manila  - The ranks of Muslim Abu Sayyaf rebels on a southern Philippine island dwindled to less than 100 after the group failed to generate ransom from freed Italian Red Cross hostage Eugenio Vagni, a military official said Tuesday.

Major General Juancho Sabban, head of a local anti-terrorism task force, said many Abu Sayyaf guerrillas deserted the group after the captive International Committee of the Red Cross (ICRC) volunteer was released Sunday without ransom.

Vagni and two other Red Cross volunteers - Filipino Mary Jean Lacaba and Swiss Andreas Notter - were seized on January 15 on Jolo island, 1,000 kilometres south of Manila.

Lacaba and Notter were released separately in April.

"As you can see it has been almost six months and nothing was paid to them," Sabban said. "Our latest count is that the group has only about 70 members from 200 because many of them deserted the group."

Sabban expressed confidence that if the government will strictly adhere to its policy of not paying ransom to the Abu Sayyaf rebels, the group will eventually disintegrate.

Vice Governor Lady Anne Sahidullah, who led the negotiations for the release of the ICRC hostages, said Vagni was freed by Abu Sayyaf leader Albader Parad on the prodding of his two wives who were arrested by security forces.

Parad's two wives were released from military custody on the same day Vagni was freed.

The Abu Sayyaf is the smallest and most violent Muslim rebel group in the southern Philippines. The group has been blamed for some of the worst terrorist attacks and other high-profile kidnappings in the country. (dpa)