Four Dead In Manila Bus Bombing; Investigation Starts

A bomb exploded on a bus in the Philippine capital on Tuesday, killing four people and wounding 14, and officials said they could not rule out terrorism as they began an investigation into the blast.

Several rebel groups including communists and Islamists are battling security forces in various parts of the Philippines, a staunch U.S. ally, but attacks in Manila are rare.

The explosion happened at around 2 p.m. (1 a.m. EST) when the bus was on a highway in the main business district of Makati, as it was nearing a railway station.

"The affected area is the sixth row, right side of the bus. Apparently the explosive was placed underneath the passenger seat, because the effect of the explosion was massive in that area."

President Benigno Aquino, who was due to speak at a hotel in Makati on Tuesday evening, said an investigation would determine whether the explosion was caused by a bomb and "does it ... point to a particular group that is fond of using that particular method of terrorizing the community".

The bombing came about three months after a number of foreign embassies had warned of a heightened risk of attacks in the Philippines, including the capital, which the government had said was not warranted.

Aquino said no country was immune from the terrorist threat, and security forces would review their risk assessments.

The explosion came six years after a similar incident in Manila that killed six people. Abu Sayyaf, a Muslim rebel group linked to Al Qaeda, had claimed responsibility for that blast and two other bombings in the south of the country on February 14, 2005, that killed 13 people and wounded more than 150.

Abu Sayyaf also claimed responsibility for a February 2004 bombing of a ferry near Manila Bay that killed more than 100 people, and bombings in Manila on December 30, 2000, that killed 22 people and wounded nearly 100.