As Pakistan started three days of national mourning Wednesday, the Taliban said they targeted a school that mostly admits soldiers' children because the students aspired to follow in their fathers' footsteps and target militants.
Terrorists ambushed the school in Peshawar on Tuesday, explosives strapped to their bodies, and burst into an auditorium filled with students taking exams.
They sprayed bullets rapidly, killing 145 people. Of those, 132 were children, authorities said.
In an email, the terror group warned Muslims to avoid places with military ties, saying it attacked the school to avenge the deaths of children allegedly killed by soldiers in tribal areas.
It accused the students at the army school of "following the path of their fathers and brothers to take part in the fight against the tribesmen" nationwide.
The Army Public School and Degree College is home to about 1,100 students and staff, most of them sons and daughters of army personnel from around Peshawar. The public school admits children whose parents are in the military, but its classes are not restricted to future soldiers.
A day after the massacre, Pakistani Prime Minister Nawaz Sharif lifted a moratorium on the death penalty for terrorism cases.