A powerful explosion ripped through a market in Peshawar city in northwest Pakistan on Monday,killing at least four persons hours after a suicide car bombing by the Taliban in Karachi killed eight persons. The explosion targeted a shop selling CDs in Nishatarbad area of Peshawar,officials said. A woman was among the dead. More than 30 people were injured by the blast,which triggered a massive fire that engulfed several buildings,shops and cars. The bomb was hidden in a motorcycle,Khyber-Pakhtunkhwa Senior Minister Bashir Bilour told the media. The blast was heard from several kilometres away. Rescue efforts were hampered by a power outage in the area. The injured were taken to a nearby hospital. Footage on television showed several shops on fire as thick smoke rose over Nishtarabad Chowk. 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.