UPDATE 1-Board of Brazil's Usiminas removes CEO Souza -sources

SAO PAULO, March 23 (Reuters) - The board of Brazilian steelmaker Usinas Siderúrgicas de Minas Gerais SA removed Chief Executive Officer Rômel de Souza on Thursday after several board members accused him of breaching company policy during negotiations with a subsidiary last year, three people with knowledge of the matter said.