An unidentified man tossed the fragmentation grenade inside the house of a certain Susan Seminilla through a window then quickly fled, Chief Insp. Rolly Oranza, chief of the Arakan municipal police said.
Oranza said no one was hurt in the explosion, but the bombing triggered panic in the farming community.
Police are still trying to establish the identity of the man who threw the grenade and the motive for the attack.
The communist New People’s Army operates in the hinterlands of Arakan, a mountainous town in North Cotabato bordering the Bukidnon province.
Earlier, police said the NPA has been mulcting villagers of revolutionary taxes, especially now that farmers have started harvesting agricultural crops.
On Tuesday night, seven people were hurt in a homemade bomb explosion at a park in General Santos Santos City plaza while three policemen were wounded in Magpet, North Cotabato, Wednesday morning when suspected NPA rebels set off roadside bombs.
Chief Supt. Lester Camba, police regional director for Central Mindanao, said police and military authorities were on top of the situation and that the separate explosions were not related.
An explosion also rocked Lamitan City Tuesday night.