A homemade bomb ripped through a bar near an army base in the southern Philippine island of Jolo, wounding six people, officials said Sunday.
Experts were sifting through the damage for clues in late Saturday's attack.
"Six people are wounded in the blast, four women and two soldiers, and we are still investigating the explosion," said Army Major Roel Ebreo, spokesman for an anti-terrorism task force.
No group claimed responsibility for the bombing, but previous attacks in the south have been blamed on Abu Sayyaf and Jemaah Islamiyah (JI) militants.
"We are determining what type of explosive was used and who is behind this blast," provincial police chief Julasiri Kasim said.
Abu Sayyaf, a small gang of Islamic militants that security experts said once received funding from Al Qaeda, has been blamed for the worst terror attacks in the nation's history.
In February 2006, Abu Sayyaf militants bombed a bar outside a base in Jolo, killing three people and wounding more than two dozen others. A month later, Abu Sayyaf bombed a store in Jolo town, killing nine people and injuring more than 20.
Abu Sayyaf is now on the run from troops in the south, but remnants often regroup in jungle camps where they are said to be training with JI militants.
The JI is blamed for other attacks in the region, including the night club bombings in Bali, Indonesia, that killed 202 people, mostly foreign tourists. (AFP)
Six wounded in Philippine bomb blast: army