The attack happened outside the Askari Bank in Peshawar, the capital of North West Frontier Province bordering Afghanistan.
Mohammed Khan, a police official, said all 12 people injured in the blast were in a stable condition.
The explosion also damaged several vehicles and smashed office windows.
Pakistan is a key ally of the US in its campaign against terror.
In recent years, Peshawar and many other parts of the Islamic nation have been hit by scores of bomb attacks, most blamed on outlawed domestic groups.
Last Mod: 08 Eylül 2007, 12:33