Explosion in Isulan comes days after another blast in the same southern city killed three people.

A bomb has ripped through an internet cafe in the southern Philippines, killing at least one person and wounding 15 in the second deadly blast to attack the same city in days, according to authorities.

Isulan, on southern Mindanao island, was placed on lockdown to hunt down those behind Sunday’s attack, said Brigadier General Cirilito Sobejana, an army division commander.

“We believe that the suspect is still inside,” Sobejana told reporters.

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

There was no immediate claim of responsibility, but authorities’ suspected that the ISIL-linked Bangsamoro Islamic Freedom Fighters (BIFF) group was behind the explosion.

“It is the BIFF who is responsible,” Sobejana told AFP news agency, adding that “this group is out to sow chaos.”

Earlier this week, three people were killed and 35 wounded when a bomb concealed in a bag went off near a night market in Isulan.

In July, at least 11 people, including soldiers and civilians, were killed and seven others wounded after a bomb exploded in a van in the island province of Basilan in the southern Philippines.

Several armed groups are active against government forces in the south of the Southeast Asian country, where a decades-long rebellion has claimed more than 100,000 lives.

The recent blasts follow President Rodrigo Duterte‘s government enacting a law to create greater autonomy for the Muslim minority in the south which is hoped to help end the conflict.

Southern Philippines, especially the Mindanao region, has been on high alert since ISIL-linked fighters laid a five-month long siege in Marawi City last year.

The region is currently under martial law, which was declared by Duterte in May 2017, and later extended by Congress to the end of 2018.