Secondary schools have been ordered closed across Nigeria's north-eastern state of Yobe after a massacre in which suspected Islamist extremists killed 22 students and torched their school.
Yobe Governor Ibrahim Gaidam condemned as "cold-blooded murder" Saturday's attack on the Mamudo boarding school.
Nigeria blamed Islamist militant group Boko Haram - which targeted two schools in the region in June - for the attack.
The group's name translates as "Western education is forbidden".
Dozens of schools have been burned in attacks by Islamists since 2010.