The victims were part of a group of 41 female students traveling in a luxury bus hired by a parochial school to take the girls to Lagos for Easter celebrations, the Nigerian Tribune reported Wednesday.
Robbers stopped the bus on the Sagamu-Ore-Benin Expressway in Orgun State on Saturday and raped the students.
A spokesman for state police said the bus driver has already identified one of the suspects.
Investigation of the incident is continuing. It is not known if police are seeking more suspects and whether all or some of the 41 girls on the bus were assaulted.