Pakistan has recently been hit by a string of bomb blasts linked to the Taliban as fears grow that the group is exacting revenge for a six-week military offensive by the country's military against its fighters in three northwest districts.
A suicide attack killed at least 15 people in a luxury hotel in the same city on Tuesday.
Armed men entered the Pearl Continental hotel and fired at security personnel before detonating explosives, government and security officials said.
Peshawar is the capital of the North West Frontier Province (NWFP) where Pakistani government forces have battled fighters loyal to the Taliban in recent weeks.
The Pakistani military launched its offensive in the NWFP after Taliban fighters violated a deal that was to see stricter implementation of Islamic law for the region's three million people in exchange for peace.
More than a dozen bomb attacks have killed at least 100 people across Pakistan since the Pakistani military began its offensive in the NWFP in late April.