Four children have been killed and one wounded in southern Afghanistan when unexploded weaponry they were playing with blew up.

Four children have been killed and one wounded in southern Afghanistan when unexploded weaponry they were playing with blew up, an official said Saturday.

The children aged between six and ten found the "unexploded ordnance" in Pajwayi district of volatile Kandahar province on Friday and brought it home, provincial spokesman Jawed Faisal told AFP.

Blasts caused by unexploded weaponry left in Afghanistan from three decades of war have caused the deaths and injuries of many children and adults in the country.

According to a recent UN report, child casualties from Afghan conflicts rose by over a quarter last year with an average of nearly five children killed or injured every day in 2011.