The blast happened as the bus travelled through the main business district in Manila Two people have been killed and several others injured in an explosion on a bus in the Philippine capital, Manila.
Police said the blast was believed to have been caused by a bomb placed under a passenger seat in the middle of the bus.
One official said the blast was so powerful it blew a hole in a nearby concrete fence.
The blast happened in the Makati business district of the Philippine capital at 1400 (0600GMT).
“Initially, we have two confirmed deaths and 15 others are injured and are being attended to in hospitals,” Nicanor Bartolome, head of the Metropolitan Manila district police office, told local television.
He said that from the damage to the bus it appeared that a bomb had exploded.
A presidential spokesman said police were working to identify what kind of device had been used.
“We were informed… that the cause of the explosion is that it was some sort of explosive device placed in the vicinity of the middle of the bus, but the exact type has yet to be determined,” Edwin Lacierda said.
He had said earlier the explosion appeared to have been caused by a mechanical or electrical fault.
The incident comes three months after the US and some Western governments amended travel advisories to warn that attacks in areas including Manila were likely.
Both communist and Islamist rebel groups are fighting security forces in parts of the southern Philippines but attacks in the capital are rare.
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