We present direct observations of electric-field induced changes in the local ferromagnetic (F) domain structure in films formed from inclusions of F cobalt in an antiferromagnetic host of BiFeO3. Piezoelectric force microscopy was used to demonstrate that the composite Co-BiFeO3 films display ferroelectricity. Strikingly, magnetic contrast changes in magnetic force microscopic images were found with the application of a perpendicular electric field. These are the results of an exchange interaction between Co and BiFeO3.