At least 11 people were injured when a grenade exploded in the southern Philippine province of Sultan Kudarat, local police said Sunday.

An unidentified suspect hurled a grenade near a gasoline station along the national highway in Isulan town Saturday night, the Police Regional Office said.

The incident took place on the eve of a festival in Isulan.

Those injured were immediately brought to hospital for medical treatment.

Authorities have launched an investigation to determine the motive and those behind the attack.

Souces: XINHUA