Brown, who is the United Nations Special Envoy for Global Education, was speaking after the same terrorist group yesterday released 158 women and children taken during a separate raid on Katarko, in December.
They were held captive for more than a month before finally being freed and reunited with their families.
The circumstances of their release according to a statement from the UN are still unclear but it may spark hopes that the Chibok girls can finally be returned home.
Brown said families had suffered 10 months of “cruelty and anguish” not knowing their fate. Despite a worldwide campaign, BringBackOurGirls, their whereabouts remain unknown.