Officials also vowed to launch a top-level inquiry into why intelligence that warned of a potential attack at the busy downtown marketplace where Friday's blast occurred was not acted upon to prevent the attack.

Interior Minister Aftab Ahmed Khan Sherpao told The Associated Press that a joint task force of federal police and intelligence agencies was formed to investigate the blast, which targeted security forces and injured 71 people, mostly bystanders.

The attack at the open-air restaurant frequented by police happened shortly after protesters clashed with authorities as the city's Red Mosque reopened for the first time since the army ousted Islamic militants in a bloody raid two weeks ago.

Police found a torso and head among the wreckage they believe are the remains of a suicide bomber.

Sherpao said identification of the remains was being hampered because they were mangled in the blast. A search of the national identity card database had so far failed to reveal any leads, he said.