Autonomous Region in Muslim Mindanao (ARMM) health chief Elias Sana confirmed that 22 people have so far died as a result of the explosion.
Sana said the bomb exploded outside a jampacked gymnasium Sunday, at the start of an inter-municipal basketball game. The attack is believed to have been meant to kill re-electionist Parang Mayor Vivencio Bataga.
Bataga survived the blast but was wounded and is still undergoing surgery for 29 shrapnel wounds in the right side of his face and upper abdomen.
Tension here worsened as relatives of the blast victims prepared to retaliate, blaming the rivals of Bataga for the attack.
Bataga, 57, had blamed political enemies for the attack but did not identify them.
"I myself am convinced that my rivals were behind the bombing," Bataga told The STAR. "Even so, we shall deal with them the legal and humane way through the forthcoming May electoral process. The voters will decide on what to do with them through the ballots."
Muslim regional leaders have confirmed that members of at least three large Muslim clans in Parang, whose relatives were either killed or wounded in the bomb attack, have begun bracing for a possible bloody confrontation with certain political leaders they suspect masterminded the bombing.
As many as 87 people, including children as young as nine, were wounded in the powerful blast.
"Last Sunday night they were roaming around, as if challenging the relatives of the people they suspect of having a hand in the bombing to a fight," a member of the Parang municipal council said. "Security preparations are now underway to prevent escalation of hostilities here."
Among those killed in the bomb attack was a pregnant member of Parangs influential Tomawis clan, a son of the vice mayor of Barira, Maguindanao and a soldier in Batagas bodyguard detail.
Nantes said the mainly-Muslim residents of Parang traditionally buried their dead as soon as possible and some of the families of the fatalities might have buried them even before police could confirm their deaths.
It is the fourth such bomb attack in the past year against Bataga, who is running for re-election in the May polls.
A former Army colonel who has fought Muslim rebels, Bataga is the first Christian mayor of Parang in Maguindanao, where political conflicts often turn violent and political clans traditionally maintain large numbers of armed followers.
Armed Forces of the Philippines (AFP) vice chief and spokesman Lt. Gen. Rodolfo Garcia promised that the people behind the carnage will be unmasked in due time.
Garcia said that, while everybody believes that local politics was the motive behind the attack, military and police probers are not ruling out other possible motives for the bombing.
"The primary angle that is being looked into is still the political angle, meaning this might have bearing in relation to the ongoing political contest or feuds between contending forces in Parang," he said.
Garcia also downplayed reports that because Parang is a mainly Muslim town, Batagas attackers may be Muslim rebels who want to kill Bataga, the towns first Christian mayor and a former Constabulary colonel.
Parang, he said, is a mixed municipality in terms of population, with Muslim and Christian residents.
AFP Southern Command chief Lt. Gen. Roy Kyamko said the bombing was related to politics and not a terrorist attack, though no suspects have been identified.
Roadblocks have been set up around the town and police are trying to trace the owner of the motorcycle used in the attack, said ARMM police director Senior Superintendent Isnaji Bantala.
The motorcycles gasoline tank was packed with explosives and parked by the suspected bomber near the bleachers of the gymnasium where Bataga and his party sat.
The bomb exploded while hundreds of people packed the gymnasium to watch an inter-municipal basketball game, investigators said.
Bataga had earlier survived two bomb attacks by suspected partisans and an ambush by gunmen on his way home from his office.
He is known for his strong anti-insurgency stance and his iron-fisted policy in dealing with lawless elements operating in Parang.
Military bomb experts said the explosive used in the attack was fashioned out of a live 81mm mortar round, highly combustible powder and rigged with a battery-operated blasting device. It was also packed with nails and jagged fragments of cast iron. The bomb was triggered by a cellular phone, Parang police chief Oscar Nantes, said.
Maguindanao Gov. Datu Andal Ampatuan, who chairs the provincial peace and order council, has condemned the bombing, branding it a "satanic and cowardly act."
Ampatuans office has released an initial P10,000 in cash assistance, which was channeled through different hospitals in Cotabato City and will be used to procure anti-tetanus vaccines for the blast victims.
They have ruled out the involvement of the separatist Moro Islamic Liberation Front (MILF), or foreign terror groups, like the al-Qaeda-linked Jemaah Islamiyah (JI), in the blast.
MILF spokesman Eid Kabalu denied his group was behind the blast although the MILF has a history of using mortar shells to make bombs.
House defense committee chairman and Surigao del Sur Rep. Prospero Pichay Jr. condemned the Parang bombing as he pushed anew for an expanded ceasefire until after the May elections to ensure orderly and peaceful elections.
Pichay said, "the bomb blast, which was apparently intended to silence a political figure, justifies the need to extend the ceasefire until after the May polls to allow the electorate to choose freely their candidates in a peaceful manner and atmosphere."
Elections in the Philippines are considered to be among the most violent in Asia particularly in Mindanao were firearms and explosives are readily available.
Military statistics show that at least 98 people including 24 government officials were killed in election-related violence in the run-up to the last congressional elections in May 2001.
The toll was the highest since the fraud-tainted snap presidential elections in 1986 when 153 people were killed. With Jaime Laude, Roel Pareño, AFP