Munir Ahmad Farhad, spokesman for the governor of Balkh province, say "at least 13 civilians" were killed Saturday by unidentified gunmen.
He says the gunmen stopped the vehicles the civilians were in as they drove through the Zareh district.
Zareh is in a remote, mountainous area of Balkh, which borders Uzbekistan. Farhad says police are investigating the incident, AP reported.
Until this year, the northern provinces were largely free of the violence that has blighted Afghanistan in a Taliban-led insurgency for almost 14 years.
With the launch in April of their summer offensive, however, the insurgents have spread the fight to almost every corner of the country.