Videos of the students abducted from the Federal College of Forestry Mechanisation, Afaka, Igabi LGA of Kaduna state, have surfaced online.
At least 30 of the students were reported missing after suspected bandits attacked the school in the early hours of Friday.
The Kaduna state government said 172 students and eight staff members were rescued from the bandits, but the whereabouts of the remaining students were unknown.
The abduction is the latest in a series of attacks by bandits across schools in northern Nigeria.
In the videos which surfaced online on Saturday, the students were seen sitting on the floor in an unknown location, guarded by armed men whose identities were concealed.