Early reports suggested that it was unclear what the attacker was targeting, although an AFP report quoted a witness claiming that an international coalition vehicle had passed through the area shortly before the explosion.
AFP quoted the International Security Assistance Force (ISAF) as saying its soldiers had not been attacked.
The governorate's deputy chief of police, Gholam Dastagir, said the bomber appeared to be from Pakistan or Chechnya.
On May 19, a bomber killed three German soldiers and at least five Afghan civilians in the city of Konduz. Reports varied as to whether five or six Afghans died in the attack.
Afghan President Hamid Karzai today condemned the May 19 bombing, saying the "enemies of Afghanistan" will never block the country's progress.
German officials from the governing coalition responded to that country's worst casualties in Afghanistan in four years by dismissing any suggestion the attack might prompt Berlin to withdraw troops.
(AFP, Reuters, dpa)