A bomb tore apart a bus in the Philippine capital Manila, killing at least three people and wounding more than a dozen others.
The bus exploded on the outskirts of Manila around 10:00 p.m. local time Friday. Police say it is unclear who set off the bomb.
The national head of police operations, Vidal Querol tells local television reporters he can not speculate on who is responsible. He calls the blast an "evil act" and says it is time for the police and the public to act together to fight bombings
A woman passenger says she was sleeping in the back of the bus and was wakened by the blast. She managed to crawl out of the wreckage.
The blast came a day after two bombs killed seven people in the southern Philippine city of Zamboanga. Around 150 people were wounded. Police are hunting four suspects they think are responsible for that explosion, but have not said who the suspects are.
Throughout the day Friday, Manila has suffered bomb scares. A grenade went off in the city's financial district early in the day and police have investigated several bomb threats.
Several violent insurgent groups operate in the Philippines. Among the more prominent rebel groups are the Abu Sayyaf, a militant Islamic group that operates in the southern Philippines and the New People's Army, which is active in the central part of the country, close to Manila.
Police have been on high alert across the Philippines since last Saturday, when bombs killed at least 180 people on the Indonesian island of Bali. No one has been arrested in that case either, but suspicion has fallen on the the al-Qaida terror network and Jemaah Islamiah, a militant Islamic group that is active throughout Southeast Asia, including the Philippines.