MANILA, Philippines — A bomb concealed in a bag exploded late Tuesday, leaving at least one dead and 35 others wounded during a town celebration in the southern Philippines, a military commander said. The attacker was chased but managed to escape, he said.

Police said two people were in serious condition after the blast in Isulan town in Sultan Kudarat province. The attack happened despite heavy security and road checkpoints in the region due to threats from Muslim militants.

A civilian told authorities about a suspicious bag left by a man near the gathering, regional military commander Brig. Gen. Cirilito Sobejana said. The bomb exploded while troops were running after the suspect, who escaped in the confusion, he said.

A regional police spokesman, Superintendent Aldrin Gonzales, gave a different account and said the homemade bomb was placed on a motorcycle parked in front of a store near a popular night market in Isulan, which was celebrating its founding anniversary.

"The area has been put under control, it's been cordoned and the injured have been taken to the hospital," Sobejana told reporters.

No group immediately claimed responsibility for the attack.

Government forces have been on alert in restive regions of the south in recent weeks due to intelligence reports that Muslim militants, who have sustained battle setbacks in government offensives, planned to carry out bombings in public areas, military officials said.

Last month, a bomb-laden van exploded in a powerful blast in southern Basilan province that killed 11 people, including the suspected foreign militant who drove the vehicle.

The Islamic State group claimed responsibility for the July 31 bombing, saying the attacker was a Moroccan. However, it cited a greatly inflated military death toll.