The Pakistan Taliban Tehreek e Taliban Pakistan (TTP) claimed responsibility for the attack Tuesday.
Pervez Khattak, chief minister of the northwestern province of Khyber Pakhtunkhwa, said over 80 of the injured are children ranging from 12 to 16 years of age.
He added that two of the attackers are now dead one blew himself up, while the other was killed by security forces.
Earlier, Shahram Khan, the province’s health minister, told CNN that two teachers and an army official had also been killed, while 104 more were wounded.
A person claimed that six suicide bombers entered the school compound with orders to kill older students. He added that “300 to 400 people are under custody of the suicide bombers” and that they are in contact with them.
The attack was revenge for the killing of hundreds of innocent tribesmen during repeated army operations in provinces including South Waziristan, North Waziristan and the Khyber Agency all restive regions along Pakistan’s border with Afghanistan.