It was Thursday that an attack occurred on a state agricultural college on the outskirts of the state of Kaduna in northwestern Nigeria.
180 people were rescued by the military early on Friday morning, but around 30 students were missing.
Now another nine students have been found missing, Reuters reports on Saturday.
Who is behind Thursday's attack is still unclear, and search efforts are now underway for the missing students.
The raid is the fourth against schools in Nigeria since December alone, when over 300 schoolboys in the state of Katsina and at the end of February, 279 schoolgirls were abducted in the state of Zamfara.
In both cases, most of the children were released.