At least 15 people including four policemen were killed in a suicide bombing in a Pakistani city near the troubled tribal areas Monday, police said. Over 20 persons sustained injuries in the attack. Police suspected that a military convoy that had just passed the place where the bombing took place was the target of the attacker. The bomber, who was also killed, blew himself up in an auto rickshaw at Afsar Chowk in Bannu. Emergency was declared in Bannu hospitals where the wounded people were shifted. Pakistan Army spokesman Maj-Gen Arshad Waheed confirmed the casualties.