SHARIFF AGUAK, Maguindanao del Sur (AP) — Four people were injured after an alleged grenade launcher explosion rocked Sitio Malinis in Barangay Mother Poblacion around 9:45 p.m. Thursday, authorities said.

Police identified the wounded as Ryan Pendatun Obpon, 51; Abdulazis S. Saludin, 20; Nasrullah Dukay Unayan, 27; and Jonalyn A. Mamay, 24. All are residents of Shariff Aguak.

Three of the victims were taken by bystanders to IPHO–Maguindanao del Sur, while one was brought to the Sulaik Clinic and Hospital for treatment.

The blast also damaged a Toyota Avanza with plate number DAS 6695 and a greenish gun-metal metallic finish, owned by Jeffrey Sulaik, according to the initial report from the Shariff Aguak Municipal Police Station.

Police officers cordoned off the area and launched a preliminary investigation. The station said it has coordinated with the Provincial Explosives and Canine Unit and the Provincial Forensic Unit (SOCO) to process the blast site.

Security forces, including the Armed Forces of the Philippines and nearby police stations, are helping pursue the still unidentified suspects.

Authorities are investigating the type of explosive used, who carried out the attack, and the possible motive.

The case remains under investigation.