The incident occurred when an object the children were playing with exploded on Monday in the Waharoade neighbourhood of the capital's southern Huriwa district

"The two dead children were buried immediately while the injured one was treated in Madina Hospital," a medical officer in the hospital said.

Relatives could not say whether the explosive that detonated was a grenade left behind in recent fighting between the rival clans or unexploded ordnance abandoned by armed militia who have been clashing in the area for several years.

Inter-clan fighting has flared regularly in the shattered Horn of Africa nation since the ouster of dictator Muhammad Siad Barri in 1991 split the vast desert country of 10 million people into a patchwork of fiefdoms governed by regional commanders.