The incident took place at 11:45 A.M on Wednesday in Faryab Province, 250 miles northwest of Kabul.
There was no immediate claim of responsibility, but Taliban militants and other groups have carried out similar attacks in the past.
The bomber detonated an explosive belt after being spotted by a security guard in the main market. The area is not one of the centers of Afghanistan’s ongoing violence, but clashes have flared in the recent weeks between government troops and Taliban insurgents.
There were various reports on death toll. A local official said at least 15 people were killed and 38 injured — some seriously — suggesting the death count could rise.
Speaking by telephone from the area, Faryab’s deputy governor, Abdul Satar Barez, said at least 25 people were killed, including two members of security forces. The reason for the conflicting accounts was not immediately clear.
“Among the wounded are some with critical conditions,” he said.
He added that the intended target was unclear, and the attacker triggered the explosives before he could be detained.