BAGUIO, Philippines -- A time bomb exploded at the Philippine Military Academy today at the precise spot where President Corazon Aquino is due Sunday, killing four people and wounding at least 45, authorities said.
Military sources said it was possible the bomb was planted by personnel in the academy -- the Philippines' version of West Point and a hotbed of opposition to Aquino and her peace-making policies with the country's 24,000 communist insurgents.
Aquino said she would go ahead with her trip to the academy and would visit the wounded Thursday at four hospitals in Baguio.
No group immediately claimed responsibility but Defense Secretary Rafael Ileto said communist were responsible for the bombing, the first at the academy.
The explosion, which officials said was equivalent in power to 100 sticks of dynamite, went off as cadets were rehearsing for their graduation ceremony, which will attended by Aquino, Illeto and armed forces chief Fidel Ramos.
The Armed Forces vice chief of staff, Lt. Gen. Salvador Mison, said the bomb ripped through the grandstand below the podium from which Aquino was to address graduating cadets Sunday. The blast also blew off half the grandstand's concrete roof, part of the walls and scattered debris up to 100 feet.
A colonel in Baguio, who requested anonymity, said the bomb was obviously meant for Aquino and apparently was rigged to explode when Aquino addresses the graduates, but went off prematurely. Police officials, however, said it was unlikely the bomb could have been timed to go off in four days.
Meanwhile, guerrillas of the Communist New People's Army used land mines and automatic weapons to kill 19 soldiers and wound seven others in an ambush -- the worst setback for the government since a 60-day cease-fire with the insurgents lapsed Feb. 8.
An academy spokesman, Col. Antonio Alviar, said a lieutenant colonel, two soldiers and a woman were killed. The woman was the widow of a soldier killed in action and was at the academy to accept an award on behalf of her husband.
Alviar said 45 people were wounded. They included the school's assistant superintendent and 15 other officers, five enlisted men, two cadets and 22 civilians.
A full investigation was under way, authorities said.
Ileto said the bomb apparently was planted on the roof of the grandstand at the academy's huge parade ground. Armed forces radio said pieces of a clock were found at the site, indicating the device was a homemade time bomb.
Ramos described the bombingas a 'dastardly act' and vowed the perpetrators would be punished severely.
The explosion blew off half of the grandstand's concrete roof and part of the flooring and crumbled walls. About 50 people were in the grandstand, watching the rehearsal, when the bomb went off.
U.S. helicopters airlifted some of the wounded to the nearby American air base at Clark Field.
Aquino held an unprecedented meeting with 23 representatives of the academy's cadets last week in a bid to win military support for the nation's new constitution.
The charter was approved overwhemingly in a plebiscite last month but returns showed that the Aquino-endorsed constitution fared poorly among the military -- including cadets at the academy, the Philippines' version of West Point.
The new constitution revives the U.S.-style presidential system for the first time in 14 years.