Manila: A grenade explosion inside a cockfighting arena in the restive southern Philippines has killed two spectators and wounded dozens.

Police said that a man tossed the grenade in the crowded arena during a town fiesta today. Muslim rebels and criminal syndicates are active in the area, but regional military commander Col. Leopoldo Galon says the explosion is believed to have been triggered by a personal feud.

The blast occurred in North Cotabato province, where extortion was blamed for a bus attack that killed two people earlier in the week.