Hostage campaign intensifies

The Abu Sayyaf has been demanding the government call off its military offensive

MANILA, Philippines (CNN) -- The Philippine army is intensifying its operations against Abu Sayyaf separatists who claim to have beheaded an American hostage.

Troops searching the area have found no sign of the body, but did find two torsos, neither of which are that of the American, officials say.

Abu Sabaya, spokesman for the Abu Sayyaf, told Radio Mindanao Network on Tuesday that the group killed Guillermo Sobero, 40, one of three Americans kidnapped May 27 from an island resort, where he had been on a diving trip.

Sabaya added the Abu Sayyaf has also stopped negotiations with the Philippines government for the release of the remaining hostages.

QUOTE "Our gift for Independence Day is one of our friends, Guillermo Sobero, but he has lost his head. It's up to you to find him and hurry up." - Abu Sabbaya, Abu Sayyaf spokesman

Philippine National Security Adviser Roilo Golez told CNN that authorities found the torsos of two native Filipino men on the island of Basilan, where the Islamic guerrillas said they had beheaded the American.

An intelligence report said one of them voluntarily went to Abu Sayyaf and tried to negotiate for the release of the hostages. His body was found later on. Neither man was a hostage from any recent kidnapping, Golez said.

Philippine officials have thus far been unable to confirm the death of the hostage but Philippine President Gloria Macapagal-Arroyo, the U.S. Government and the Vatican have condemned the beheading claim.

Two more battalions of Philippine marines are expected to arrive in Basilon, a mountainous, jungle island 900 kilometers (560 miles) south of Manila, where more than 1,000 army and police officials have been tracking the kidnappers.

VIDEO The family of a hostage rebels say is dead holds onto hope. CNN's John Raedler has more (June 12) Play video (QuickTime, Real or Windows Media)   IN-DEPTH Abu Sayyaf: Militants in the Philippines   •  Background   •  Interview script   •  Incident map   •  Message board    COUNTRY PROFILE At a glance: Philippines Provided by CountryWatch.com    CNN.com Asia More news from our Asia edition

The Philippine government, together with the U.S. State Department, are looking into the reports of the killing of the hostage as troops searched a 500-square-mile area on the eastern side of Basilan island for the body of the hostage.

"There is no official confirmation," Golez told CNN. "We are waiting for word from our men in the field but Abu Sayyaf mentioned quite a big area where we have to find the confirmation."

The U.S. State Department called the beheading report "credible" but pointed out that Abu Sayyaf has been known to "fake things" in the past.

Earlier, the U.S. Embassy in Manila issued a statement condemning the reported killing as a "cowardly act."

"We hold the Abu Sayyaf group responsible for the safety and welfare of the people it is holding," the statement said. "We call for the safe, immediate and unconditional release of the innocent persons being held."

The Vatican also condemned the hostage beheading claim, with Archbishop Antonio Franco on Tuesday expressing confidence that President Arroyo will work through the crisis.

Resolve hardened

For her part, Arroyo appeared even more determined to crush the Abu Sayyaf.

Speaking at a diplomatic reception to celebrate Independence Day in the Philippines, Arroyo said the Abu Sayyaf has trampled on the values of Islam and humanity.

"To murder and even behead a helpless person is as ruthless as it is cowardly," she said. "The reported murder of Mr. Sobero only strengthens our resolve to decimate, once and for all, this cold-blooded bandit group."

Abu Sayyaf says it is fighting for an independent Islamic state in the southern Philippines islands and has threatened to behead more hostages.

Philippine officials refused to respond to the threat saying they cannot afford to be "hamstrung."

"We have to go by our strategy which is, number one, military offensive," National Security Adviser Roilo Golez told CNN. "Our troops are there because they have the unfortunate helpless, innocent victims."

"Number two, we have to stick by our policy of no ransom. We are only negotiating the unconditional release of the hostages," he said.

Golez also denied the government actions were compromising the safety of the hostages by using force to release the hostages .

"No it doesn't," he said. "I'd like to reiterate that they [the hostages] have been the innocent victims with them."

Unconditional release only

Sabaya had threatened to execute one of the Americans last Thursday and reiterated the threat to do so at noon Monday unless the Philippine government agreed to the group's demands to appoint two Malaysians -- a senator and a merchant -- to negotiate the hostages' release.

Military spokesman Brig. Gen. Edilberto Adan shows details of the military operation

Minutes after that deadline, presidential press secretary Rigoberto Tiglao announced the Philippine government would raise no objection to Malaysian senator Sairin Karno negotiating for the release, providing the Malaysian government permitted Karno to do so. He said Karno would work with a designated government intermediary, William Castillo.

Sabaya announced the rebels accepted the government's offer, provided it was sincere, and he said the rebels would call off an earlier threat to behead the three American hostages.

But even as all this was going on, the rebels took 15 more people -- including two 12-year-olds -- hostage Monday around 9 a.m. (0100 GMT). The hostages were taken in Lantawan, near the capital of Basilan, the Abu Sayyaf stronghold.

Their capture brought to 28 the number of people believed held by Abu Sayyaf.

The two Malaysians the group had sought to be negotiators helped negotiate a hostage incident last year in which a large ransom was paid after Abu Sayyaf gunmen took more than 40 people hostage from the Malaysian tourist resort of Sipadan.

Government officials have said they will not negotiate for ransom, but only for the unconditional release of the hostages. The government is offering a $2 million reward for information leading to the capture of the separatists.

The first group of hostages was taken by about two dozen Abu Sayyaf gunmen at the Dos Palmas resort in Palawan's Honda Bay in a dawn raid May 27.