The separatist Abu Sayyaf group is demanding $3 million for the safe release of two Filipinos and two American hostages in southern Basilan.

A military source said, yesterday, it had monitored Abu Sayyaf spokesman Abu Sabaya on Monday telling another rebel group in Basilan on radio that he was demanding ransom in exchange for the release of Angie Montealegre, Maria Fe Rosadeno, and U.S. missionary couple Martin and Gracia Burnham.

The four hostages were kidnapped on May 27 from Dos Palmas resort in the western island province of Palawan and taken to Basilan.

The Burnhams, from Kansas, are members of the New Tribes Mission who have been working in the Philippines for the past 15 years. A third American captive, Guillermo Sobero, from California, is presumed dead, although his body has not been found.

The Abu Sayyaf is still holding several Filipino hostages and has so far beheaded more than a dozen captives since June, when President Gloria Macapagal-Arroyo ordered a massive military assault against the rebels.

Our Manila Correspondent adds: Congressmen – possibly even senators – are set to go to Basilan on August 24 to investigate the alleged connivance by military men with the Abu Sayyaf that led to a botched operation in Basilan in June.

The prospect of a Senate-House joint investigation was raised by Deputy Speaker for Mindanao, Abdulgani Salapuddin, who said he has talked with Senator Rodolfo Biazon, Upper Chamber's defence chairman, regarding this in a recent trip to Malaysia.

"A joint House-Senate inquiry will be more powerful in our bid to ferret the truth from falsehood on the Abu Sayyaf issue. What did we learn from the exposes raised by Father Cirilo Nacorda?" Salapuddin asked.

He was referring to Nacorda, parish priest of Lamitan town, who accused top military officers of being in cahoots with the Abu Sayyaf kidnapping group.

Salapuddin allayed House Representative Prospero Pichay's apprehensions about the safety of the Congressmen who will be visiting Basilan. "I come from Basilan and I can guarantee a peaceful situation here," Salapuddin said.