Kenyan police say four children have been killed and one seriously injured after playing with unexploded ordnance they found near a military training ground.

Deputy police spokesman Charles Owino says the children had taken their cows to graze on Sunday and had found an explosive object, possibly a grenade, near the village of Ole Maroroi.

He says the children ranged in age from four to eight years old.

Ole Maroroi is around 40 miles (60 kilometers) northeast of the capital of Nairobi and near a Kenyan military training ground.