Police in northern Nigeria rescued nearly 70 men and boys from a second purported Islamic school where they were shackled and subjected to "inhuman and degrading treatments."

The raid in Katsina, the northwestern home state of President Muhammadu Buhari, came less a month after about 300 men and boys were freed from another supposed Islamic school in neighboring Kaduna state where they were allegedly tortured and sexually abused.

"In the course of investigation, sixty-seven persons from the ages of 7 to 40 years were found shackled with chains," Katsina police spokesman Sansei Bubal said in a statement. "Victims were also found to have been subjected to various inhuman and degrading treatments."