The claim of the Abu Sayyaf that it has beheaded American tourist Guillermo Sobero will remain a mystery as CNN has refused to buy the tape filmed by the rebels on the gory execution.

We will never know the truth at this point," said National Security Council head Roilo Golez, adding the government would believe the claim of Abu Sayyaf spokesman Abu Sabaya only after the recovery of Sobero's body.

"Even if CNN has bought and shown the tape on air, I doubt very much if it would be credible since it was taken by the Abu Sayyaf and not recorded by its staff," said a TV journalist who requested for anonymity.

Television networks trust only the film clips taken by their staff and crew members, or by other reliable agencies. A man claiming to be Abu Sayyaf spokesman Abu Sabaya called up to sell for $20,000 (P 1m) the tape which recorded the beheading of one of the three American hostages, CNN said.

"We are not bluffing. We have done it already," CNN quoted the man as saying. When CNN refused to buy the tape, the caller threatened to sell it to other news agencies.

Reacting to the group's money earning venture, Presidential Spokesman Rigoberto Tiglao said: "Sabaya wants to commit a crime, at the same time, make some greenbacks out of a dastardly crime."

Sabaya earlier said in a radio interview that his group had decapitated Sobero in time for the country's independence day, adding the Abu Sayyaf has photographs and video tape as proof. The next day, the presidential palace issued a transcript of Sabaya on radio, saying there was no execution.

In the same interview, Sabaya claimed that his group detained Muslim priest Ustadz Buhaymin Saji because he was suspected as a government spy. He was not beheaded as claimed by the military, Sabaya added.

Sabaya also put Sali on air who, in turn said that one of the American hostages was killed. He did not say if he personally witnessed the execution. Tiglao admitted that the presidential palace remained puzzled about the real fate of Sobero. "We are as puzzled as you are and if he says that again, he is really doing psychological torture against the victims," he said.

At the same time, President Gloria Macapagal-Arroyo was scheduled to visit Zamboanga and Palawan, southern Philippines, to personally inspect the tourism business in the areas.

"She wants to check for herself the conditions there and what can be done for the improvement of the image of Palawan and Zamboanga as well as to find out how government resources can be used to help out," said Tiglao.