MANILA, Philippines (AP) — Suspected Muslim militants on Sunday detonated a second bomb in less than a week in a southern Philippine town, killing at least one and wounding 15, a military official said.

The homemade bomb went off late Sunday near an internet cafe in Isulan town in Sultan Kudarat province, said regional military commander Brig. Gen. Cirilito Sobejana. Troops put the town in a security lockdown shortly after the attack.

"We've temporarily placed Isulan on a lockdown. We wouldn't want the suspect to go out. We believe that the suspect is still inside," Sobejana told reporters.

Three of the wounded were taken to a hospital in serious condition, Sobejana said.

A bomb concealed in a bag went off near a night market in Isulan on Wednesday, leaving three people dead and 35 wounded.

Military officials blamed both bombings on the Bangsamoro Islamic Freedom Fighters, a small but hard-line group that has aligned itself to the Islamic State group.

Philippine troops in the restive south have been on alert in recent weeks based on military intelligence that Muslim militants, suffering setbacks from battles with government forces, planned to carry out bombings in public areas.

A vehicle bombing on July 31 in southern Basilan province killed 11 people, including the suspected foreign militant who drove the vehicle. The Islamic State group claimed responsibility and identified the attacker as Moroccan. However, it cited a greatly inflated military death toll.