"We hope that with the cash reward, we will be able to solve the case immediately," North Cotabato Gov. Manuel Piñol said.
The communist New People’s Army (NPA) and the Moro Islamic Liberation Front (MILF) yesterday denied any role in the attack, which police said had all the trademarks of terrorism.
Army spokesman Maj. Julieto Ando said the NPA and the MILF have the capability to launch such an attack.
"We cannot pinpoint directly who is responsible, but there are groups that have been extorting like the NPA and the MILF," Ando said in an interview. "Both of them are our suspects."
Security forces, in the meantime, will impose tight security measures "to prevent a repeat of the incident," he said. Troops backed by armored personnel carriers and bomb disposal experts have been deployed to search for more bombs, he added.
Some 25 people were also wounded in the blast, the second in troubled Mindanao in about a week.
On Oct. 2, a nail-laden bomb in Zamboanga City killed four people, including a US Green Beret who was in the region to train Philippine counterterrorism troops.
The attack was blamed on the Abu Sayyaf, an self-styled Muslim secessionist rebel group allegedly linked to al-Qaeda. No link has been established between the two bomb blasts.
Yesterday, police announced that it had captured a ranking Abu Sayyaf member, identified as Daim Dansan, in the city. Chief Superintendent Simeon Dizon, Western Mindanao regional police chief, said they don’t know yet if Dansan, who carried a P1 million bounty on his head, was involved in the Oct. 2 bombing.
NPA spokesman Gregorio "Ka Roger" Rosal and MILF spokesman Eid Kabalu, meanwhile, denied their groups were involved in the Kidapawan blast.
"Aside from the fact that we were not behind that, we have an existing ceasefire agreement with the Republic of the Philippines," Kabalu said in a telephone interview. "If the MILF did that, what points will we score?"
Rosal told a radio interview that the NPA had nothing to do with the bombing and any such allegations by the military are meant to strengthen the claim that his group is a terrorist organization.
Muslim separatists, communist rebels and bandits operate in the area, and the bus company that lost two vehicles to the blast was targeted in a bombing nearly a month ago for allegedly refusing to pay "protection" money.
Officials said criminal gangs are also possible suspects.
The management of the terminal operator, Weena Bus Co., said it has received several letters demanding extortion payments.
One of those letters was signed by a "Suicide Bomber Team" which has bombed several business establishments in the south as part of an extortion scheme.
Police and soldiers have been deployed on Weena buses for several months after previous bombings, Superintendent Casimiro Medes, Kidapawan police chief, said.
In February 1999, two Weena buses aboard a ferry were bombed in Ozamis City, leaving scores of people either killed or wounded.
Kabalu described the blast as the handiwork of "extortionists" and said it was "un-Islamic and those responsible should be punished."
"If the MILF had its way, the suspects should be executed publicly," he said. "We ask the Philippine authorities not to point an accusing finger at us. We have nothing to do with it."
Ando alleged that the MILF in the past tried to extort money from the bus company and other businesses and that ordinary extortionists did not have the capability to plant such a powerful bomb.
He declined to give details, saying that could jeopardize investigations.
Medes said unidentified men placed a 60mm mortar shell with a timing device under a concrete bench in the bus terminal. The bombers may have left the explosive at the terminal because security on the buses was too tight, he said.
He said six people died and 25 were wounded, correcting earlier statements that eight had been killed. He believed a criminal group was behind the attack but did not single out any gang.
Three people died at the scene and three others at the hospital, in the city of 110,000 residents. The victims included a 12-year-old boy, and several of the injured were in critical condition.
The MILF, with an estimated force of more than 12,000 fighters, has been waging a guerrilla war for a separate Islamic state in the south since 1978 when it split with the larger Moro National Liberation Front which signed a peace pact with the government in 1996.
President Arroyo launched peace talks with the MILF when she assumed office in 2001, leading to a ceasefire accord that is still in effect.
Both the NPA and the MILF have said they have a "tactical alliance" in areas where they both operate.
On the other hand, the Communist Party of the Philippines (CPP) has been waging an insurgency through the estimated 12,000-strong NPA since 1969.
In August, the United States included the CPP and the NPA in its list of "terrorist" organizations as part of its worldwide war on terror.
Rebel leaders rejected the label, saying their group was decriminalized by the Philippine government after the 1986 ouster of the late dictator Ferdinand Marcos. — With Christina Mendez, Roel Pareño, John Unson, Marichu Villanueva, Paolo Romero, AFP