A suicide bomber killed an Afghan policeman and wounded five civilians in Kunduz on Thrusday, the second deadly attack on government security forces in the northern city this week.
The attacker walked up to a checkpoint in a crowded area of the city centre and blew up a suicide vest strapped to his body, officials and witnesses said.
Several of those wounded are thought to be shopkeepers working nearby.
The attack came four days after militants armed with guns and suicide vests attacked an army recruitment centre in Kunduz, killing eight people in a day-long siege.
Experts warn that the Taliban insurgency is becoming increasingly active in northern Afghanistan, having expanded from its traditional powerbase in the south, where US-led Nato troops are concentrating the fight to reverse their momentum.
When contacted by AFP, a Taliban spokesman could neither confirm nor deny responsibility for the attack.
"At around 8:00 am (0330 GMT), a man wearing a suicide vest walked up to a traffic post in the centre of Kunduz city," the head of the local provincial council, Mahboobullah Mahboob, said.
"A guard tried to prevent him from entering the post, the suicide attacker detonated explosives strapped to his body.
"One traffic policeman was killed and five civilians were injured in the explosion."
The attack was confirmed by the interior ministry in Kabul.
One man who received shrapnel injuries in the blast, 30-year-old Abdul Wakeel, told how he had gone shopping with his family on what is the first day of the weekend in Afghanistan.
"Minutes after I got there, I heard an explosion," he said, speaking from Kunduz's main hospital.
"I felt a pain in my stomach and I realised I was injured. I blame the Taliban for this explosion as they always carry out suicide attacks in crowded areas without any regard for civilians' lives."
The attack came as the UN envoy to Afghanistan, Staffan de Mistura, warned that the Taliban could attempt "spectacular attacks" in January.