The blast's impact was so powerful that several shops caved in at the market in Kohat, 60 kilometres south of Peshawar, TV channels reported.
At least 10 people were killed in the blast, they said, adding rescuers are still trying to pull victims from the rubble.
It was immediately not clear whom the bomber wanted to target, police said.
Further details were immediately not available.
(Published 18 September 2009, 06:16 IST)