KUNDUZ, Afghanistan, Feb. 14 (Xinhua) -- Seven children sustained injuries as an explosive device went off in Khan Abad district of Afghanistan's northern Kunduz province on Tuesday, district governor Hayatullah Amiri said Wednesday.

"A group of innocent children were playing on a ground in Choga village on Tuesday afternoon when they found a toy-like object and begun playing but the device exploded, injuring seven children," Amiri told Xinhua.

All the injured children have been taken to hospital, the official added.

Hundreds of thousands of mines and unexploded devices left over from the past wars in Afghanistan often cause casualties, mostly children.

A similar incident also on Tuesday in the neighboring Imam Sahib district of Kunduz province killed one child and injured two others.