The explosion targeted a shop selling CDs in Nishatarbad area of Peshawar, officials said. The blast triggered a fire that engulfed nearby buildings. The nature of the blast could not immediately be ascertained.
Rescue efforts were hampered by a power outage in the area. The injured were taken to a nearby hospital.
No group claimed responsibility for the attack. The Taliban have carried out a wave of attacks on shops selling music and movies across northwest Pakistan in the past four years.
Earlier in the day, a suicide bomber rammed his explosives-laden car into the home of a senior police officer in Karachi, killing eight persons, including a woman and her 12-year-old son.
The Taliban claimed responsibility for the attack, saying it was carried out to avenge the killing of militants by the police officer.
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