Defense Secretary Orlando Mercado said the hands of the priest, the Rev. Ruel Gallardo, were tied when he was shot in the back of the head Wednesday by escaping Abu Sayyaf rebels.
Three other people who died in the rescue attempt--all teachers--also were shot in the head at close range, according a priest who saw the bodies. At least two, both women, had apparently been hacked on their bodies and arms, the Rev. Martin Jumoad said.
Nine children and six teachers were rescued by the soldiers, who stumbled across the Abu Sayyaf rebels as they were about to cross a river, and both sides opened fire.
Many of the 27 hostages being held by the rebels were children seized from two Catholic schools in Basilan province more than six weeks ago. Five of the rescued hostages were injured, one seriously.
Several of the hostages said the rebels had beaten Gallardo regularly. Bishop Romulo de la Cruz of Basilan said medical examiners told him that the nails on both of Gallardo's big toes had been pulled out.
Relatives bawled Thursday at a wake for the victims at Basilan's cathedral.
Troops were pursuing the fleeing rebels Thursday in hopes of rescuing the remaining hostages, Mercado said.
The Abu Sayyaf is the smaller of two separatist Muslim rebel groups seeking an independent Islamic nation in the impoverished southern Philippines, a predominantly Catholic nation.
On neighboring Jolo island, a radio station reported that two foreign hostages among a separate group of 21 captives also being held by Abu Sayyaf rebels had been able to escape.
Radio station DZMM, quoting an unidentified source at the Abu Sayyaf rebel hide-out, said the two males escaped from their captors Wednesday. Rebels searching for them later clashed with military troops that have encircled the area, and one guerrilla commander was killed, it said.
Military officials said they had no confirmation of a hostage escape.
Mercado said the military also has not confirmed a claim by rebel leaders Wednesday that two of the foreign captives died during an earlier clash with troops.
The 21 hostages, including 10 foreign tourists, were kidnapped April 23 from a Malaysian diving resort and brought to the hills of Jolo in the Philippines, about an hour away by boat.
Mercado said they have since been moved and are now being held at five separate locations.
On Wednesday, troops seized the bamboo hut where the hostages had been held, but found no one inside. No bloodstains or bullet holes were evident, the military said.
The rebels have threatened to behead two foreign hostages if the military does not pull back its tight cordon of the area.
Nur Misuari, the government's hostage negotiator, also threatened Thursday to withdraw from negotiations if the military does not halt operations in the area.
Mercado, however, said the soldiers will stay put.
``The military will never retreat,'' he said. ``If the military withdraws, the Abu Sayyaf will be in control.''
Police said they had intelligence reports that the rebels were planning to kidnap foreign and local journalists gathered in Jolo, and warned reporters to stay inside an army base.
The 27 Basilan hostages were among about 50 people seized by the rebels on March 20 for use as human shields. The rebels later released some captives, but claimed to have beheaded two male teachers two weeks ago. That led the military to attack their stronghold. Troops overran the area in weekend fighting that killed 11 soldiers, but failed to find any of the captives.
The rescued hostages said they had been taken from the camp Saturday and forced to walk each night through forest trails.
``When we left the camp there were already explosions around it,'' said Criselda Selvano, a sixth grader. ``They moved us from place to place during the night. Sometimes we slept under the trees, and when it rained we got wet.''
The Jolo hostages include tourists from Germany, France, South Africa, Finland and Lebanon as well as resort workers from the Philippines and Malaysia. Journalists who accompanied a doctor to the bamboo hut Monday were able to interview the hostages, who complained of food shortages, fevers and infections. The doctor said she told the rebels that two captives need to be hospitalized, but the rebels did not immediately agree.
Elsewhere in the southern Philippines Wednesday, the larger Islamic rebel group, the Moro Islamic Liberation Front, claimed responsibility for several bomb explosions that killed a reported 15 people and injured dozens.
A bomb concealed with plastic exploded in the General Santos fish port, killing two people and seriously injuring at least 20, Mayor Adelbert Antonino said. Almost simultaneously, a bomb inside a taxi exploded in front of a municipal building, killing one woman, and a bomb outside a second city building killed one man and injured 10, he said. Police and military officials also reported explosions in Cotabato, Zamboanga del Sur and Maguindanao.
The government and the MILF began formal peace talks this year, but clashes have escalated since last Friday.
The hostage-taking and bombings have drawn new attention to the quarter-century old Islamic rebellion in the southern Philppines, where the nation's minority Muslim population is centered.