Manila: Philippine troops defused a powerful bomb found in a packed bus in a southern town yesterday, after the US Embassy warned that terrorists might carry out attacks in bus terminals, officials said.

The bomb - black explosive stuffed in a pitcher with steel fragments as shrapnel - had been concealed in a backpack on a bus where it was hastily abandoned by two men late on Sunday in southern Maguindanao's Talitay town, regional army spokesman Lieutenant Colonel Julieto Ando said.

Panicking passengers grabbed the bag and hurled it outside the bus. Police and army experts later defused the bomb, which was attached to a timer and batteries but had not been set to detonate, Ando said.

A police investigation was under way to determine whether the bombing bid could be attributed to Al Qaida-linked militants, or whether it was the fallout of lingering political wrangling following the May 14 congressional and local elections, he said.

The volatile Maguindanao region, where guerrillas and political warlords hold sway, was plagued by bombings and gun attacks because of intense political rivalries during the balloting.

Investigation

"It's hard to pinpoint who left that bomb in the bus," Ando told AP by telephone. "We had our share of bombings and gun strafing. It's impossible not to have those in an elections here." Talitay is about 100 kilometres from the towns of Kidapawan and Makilala in North Cotabato province, where the US Embassy warned over the weekend that terrorists could set off bombs in bus terminals and public markets over several days.