An Afghan teenager was killed and two others were injured in a blast caused by old ammunition that they found in some trash, a US military spokesman said on Monday. The boy died on Saturday after he collected some unexploded ordinance from a tip in Qalat, the capital of southeastern Zabul province, Major Mark McCann told AFP. On the same day in eastern Paktia province - a hotbed of activity by remnants of the ousted Taliban regime - police clashed with insurgents in a firefight that produced no reports of any casualties, McCann added.