COTABATO, Philippines, Jan. 14 (Xinhua) -- A grenade hurled by unknown men exploded on Wednesday night in the southern Philippine city of Kidapawan but there were no reported casualties, an official said on Thursday.

    Mayor of the city Rodolfo Gantuangco said motorbike-riding men lobbed a hand grenade shortly before 9:00 p.m. at a basketball court in the village of Sudapin.

    Nobody was hurt in the attack and the mayor ruled out terrorism angle in the blast.

    "Its not related to terrorism. Its personal grudge and our police is investigating it," Gantuangco said.

    On Dec. 31, three civilians were injured in a similar attack in the same city.