At least 85 die in mistaken drone hit by Nigeria army

85 people confirmed dead in military drone attack on religious gathering in northwest Nigeria; President orders probe into mistakes in conflict zones; victims include children, women, and the elderly; 66 people injured; since 2017, 400 civilians killed by airstrikes targeting armed groups; drones targeted terrorists and bandits in Kaduna state's Tudun Biri village; miscalculated airstrikes becoming worrisome in Nigeria's fight against extremist violence and rebel attacks.