Philippine authorities are investigating a bomb explosion that late Friday destroyed a bus near Manila, the latest in a series of bombings in a country fighting Muslim radicals linked to al-Qaida.
Officials say at least three people were killed and more than 20 injured when a bomb tore through the back of the bus, ripping off its roof. Authorities fear the death count could go higher.
There has been no claim of responsibility for that blast or another Thursday. But suspicions are focused on the militant Muslim Abu Sayyaf group, which has been linked to al-Qaida.
The blast Thursday killed seven people and injured 150 in the southern city of Zamboanga.
Philippine authorities have launched a manhunt for four suspects in that case, which they say was similar to an explosion earlier this month that killed four and was blamed on Abu Sayyaf.
Earlier Friday, a bomb exploded in Manila's Makati financial district causing widespread fear, but no injuries.
Security has been tight in the Philippines following a bomb attack last week at a nightclub in Indonesia.
Two bombs exploded in Bali, killing at least 180 people. Many still are missing.