Three children were killed and two others injured when a hand-grenade they were playing with exploded in Peshawar on Wednesday, reported 24NewsHD TV channel.

Local residents and Rescue 1122 officials rushed the injured to the Lady Reading Hospital after the explosion in Zangli area on Peshawar’s Kohat Road.

Police are investigating from where the children got hold of the hand grenade.

The four brothers and a neighbour were playing when they found the rusty grenade near a village in Peshawar. "The children first played with it and later hit it with a stone causing it to explode," Mansoor Aman, a local senior police official, told AFP.

Local police official Aziz ur Rehman confirmed the casualties. Old mortar, artillery shells and other discarded munitions are often smuggled into the country from Afghanistan, some dating back to the Soviet war in the 1980s.

The area was also once a hub of anti-Taliban activities, with locals forming militias to fight against the insurgents.

Last year, five people were killed when a worker at a scrap metal shop tried to recycle an old mortar shell that exploded as he tampered with it.