An improvised bomb believed planted by leftist rebels exploded in southern Philippines early Saturday wounding four government soldiers, the military said. Troops from the army\'s 25th Infantry Battalion were conducting patrol at Kalinugan, Casoon village, Monkayo town, in Mindanao\'s Compostela Valley province when they were hitting by a makeshift landmine around 2:30 a.m. Saturday, said Lieutenant Colonel Lyndon Paniza, spokesperson of the army\'s 10th Infantry Division. \"Four soldiers sustained shrapnel wounds and immediately evacuated to the regional military hospital in Davao City while pursuit operation against the rebels continue,\" Lieutenant Colonel Paniza said. The military official condemned the recent incident as the New People\'s Army\'s persistent defiance of the internal ban in the use of pressure-activated explosives as stipulated in the Geneva Convention. The 4,000-strong NPA, armed wing of the Communist Party of the Philippines, is fighting a 42-year leftist insurgency in 60 Philippine provinces.