Police and security sources told reporters that "there might be a series of bombings of vital installations, among them the Batasan Pambansa and the Sandiganbayan."
Intelligence reports also identified radio and television stations in Quezon City including ABS-CBN and GMA-7, and their radio stations, dzMM and dzBB, respectively.
Reliable sources said the bombings "might occur between 1 and 3 p.m." yesterday and today.
Sandiganbayan sheriff Ed Urieta said they had already made security arrangements with the Quezon City police and had deployed two bomb-sniffing dogs to scour the five-story Sandiganbayan building on Commonwealth Avenue for any trace of explosive devices.
"We have already scoured the area with the K-9 dogs," he said.
"We are on a heightened alert. But we are still coordinating with the local police just in case. It’s still business as usual here."
At Malacañang, Executive Secretary Eduardo Ermita said authorities are ready to confront terror threats.
"We often receive such information of possible bombings and other attacks and we make it a point to verify all of them," he said. "While we do that, we put up measures and contingencies and we’re prepared to meet such threats."
Ermita called for full cooperation from the people, particularly in reporting suspicious incidents and information that could indicate terror activities.
Last week, the Philippine National Police (PNP) set up 15 checkpoints in Metro Manila and deployed over 20,000 policemen to thwart any terrorist attack.
Metro Manila police commander Director Vidal Querol said the police are responding to consistent intelligence reports that terror groups plan to attack the metropolis.
He did not elaborate on the alleged plots or the heightened security in Metro Manila.
Also last week, Presidential Security Group chief Brig. Gen. Delfin Bangit warned that foreign terror groups are planning to attack high-profile targets.
When asked whether the terror group behind the plot is the Jemaah Islamiyah, he said: "I refer to some international terrorist group and our intelligence has been consistently monitoring these developments and this is one particular area that the PSG is very concerned with."
The JI, which operates in Southeast Asia and is reportedly al-Qaeda’s arm in the region, seeks to create a pan-Islamic state in the region.
JI militants have reportedly been training in rebel camps in Mindanao, which foreign security analysts said have been used as a logistics base, a refuge as well as a launching point in staging bombings in neighboring countries. — With Paolo Romero