Police investigators are looking into the possibility that the Magdalo group of mutineers or communist rebels may be involved, Gonzales said.
He also suspects that the perpetrators may have been involved in past efforts to oust Mrs. Arroyo and have now resorted to bombings.
"The bombings may continue until the State of the Nation Address," Gonzales said in an interview over Vice President Noli de Castro’s weekly radio program.
"The bomb attacks are connected to the current political situation. We saw a pattern that this is related to politics and that’s what we’re watching closely." Gonzales did not elaborate.
Judging from the time of the attacks and targets chosen, the bombings were apparently not meant to harm people, he said. But Gonzales did not rule out the possibility that the attacks could escalate and injure or even kill innocent people.
"These bombings at the start are harmless but the next could be harmful, so it is urgent that we arrest those responsible," he said.
Director Marcelo Ele Jr., head of the Philippine National Police’s directorate for investigation, said the bombings may be meant to destabilize the government and embarrass the police.
"Their targets are isolated because the bombings are too far away to hurt people," he said. "But if your intention is to sow fear, terror, destabilize the government, discredit the gains of the PNP in fighting criminality and undermine the institution, then we are prepared."
Over the past several weeks, bombs rocked the Grepalife Building in Makati City, ripped open a police bus in Quezon City, Camp Bagong Diwa in Taguig City, and a police station at Liwasang Bonifacio in Manila.
Ele belied reports that explosives in the blasts came from the police arsenal, saying that all explosives in their stockpiles were accounted for.
"I want to clear the misimpression that these high explosives are only found in the arsenal of PNP and AFP. These are also being used in mining and construction and are commercially available. We are running an inventory and there are no TNT and RDX unaccounted for, so we are looking at private procurement," he said.
Two little-known groups, Taong Bayan and Kawal, have claimed responsibility for the blasts.
Gonzales recently revealed an alleged communist New People’s Army plot to assassinate Mrs. Arroyo and several government officials.