Local authorities said a home-made bomb ripped through an internet cafe at around 7:35 p.m. An 18-year-old boy was killed in the incident. Three of the 15 wounded are fighting for their lives in a local hospital.
No group claimed responsibility for the blast but the Philippine government accused the Bangsamoro Islamic Freedom Fighters (BIFF) linked to the Islamic State (IS) of standing behind the bombing.
The BIFF is a breakaway faction of a Muslim separatist group which signed a 2014 peace deal with the government to end 50 years of conflict that had killed 120,000 people and displaced 2 million in the south of the mainly Catholic Philippines.
The attack happened just a few days after a bombing on August 28 also in Isulan town left three dead and more than 30 others injured.
A curfew has been in place in the southern Philippines until the end of this year since pro-IS militants launched an attack in Marawi city last year.-VNA