NEW : Islamabad 's Prime Minister Shahidullah Shahid condemns attack , cancels Davos trip . NEW : Main Pakistani Taliban faction claims responsibility , calls for fresh talks . Pakistani Taliban spokesman : Bombing was to avenge the death of a TTP commander . The blast strikes a convoy of military and civilian vehicles , killing At least 22 people .
NEW : Pakistan 's Prime Minister Nawaz Sharif condemns attack , cancels Davos trip . NEW : Main Pakistani Taliban faction claims responsibility , calls for fresh talks . TTP spokesman : Bombing was to avenge the death of a Pakistani Taliban commander . The blast strikes a convoy of military and civilian vehicles , killing at least 22 people .