The bomb went off at the entrance to a shopping mall in the city of Cotabato in the early afternoon.
A crude bomb, blamed by security forces on a small pro-ISIS militant group, killed two people and wounded dozens on Monday in the southern Philippines, an army commander said.
ISIS terrorists operate in the south of the largely Christian Asian country and some are known to have links with groups abroad, including al Qaeda and ISIS.
Major General Cirilito Sobejana, an army division commander, told Reuters the bomb bore a "Daesh-inspired signature", referring to ISIS by another name.
The bomb went off at the entrance to a shopping mall in the city of Cotabato in the early afternoon. As well as the two people killed, 28 were wounded, he said.
A second bomb was recovered in the same area, he said.
Sobejana said he suspected the blast was retaliation for the killing by government troops of seven members of a small terrorist group that has pledged allegiance to ISIS.