A soldier and three members of the leftist rebel group New People's Army (NPA) were injured in a firefight in southern Philippines on Tuesday afternoon, a military official said Wednesday. Capt. Alberto Caber, spokesman of the military's Eastern Mindanao Command, said troops from the Philippine Army's 25th Infantry Battalion were conducting a security operation at Casoon village, Monkayo town in Compostela Valley province when they encountered the leftist rebels. Caber said soldiers were able to recover an M-14 rifle, an M-16 rifle, two landmines, 200 meters of detonating cord, medical paraphernalia and personal belongings of the NPAs. Military officials said Compostela Valley province is one of the few areas where the NPA remains active due to the presence of mining companies which the leftist rebels supposedly target for their extortion activities. Meanwhile, the Philippine military announced that four NPAs surrendered to the 34th Infantry Battalion in the central Philippine province of Northern Samar last week. The 4,000-strong NPA, armed wing of the Communist Party of the Philippines, has been fighting a leftist insurgency in 60 Philippine provinces since 1969.