Armed men shot dead an Afghan man and three women working with international aid group ActionAid, police said on Tuesday.
The aid workers were on their way to a district office in northern Jawzjan province when armed men opened fire on their vehicle and killed them, provincial police chief Juma Khan Hamdard told the agency.
"Unidentified armed men today killed three women and one man working for the NGO ActionAid in Mingajik district," Hamdard said.
Police had appointed a delegation to go to the district to investigate, he said.
The group's Kabul-based programme manager, Jawed Yousufi, said there had been an attack on an ActionAid vehicle in Jawzjan, but he did not know the condition of the staff.
There have been several attacks on aid workers in Afghanistan but they have been rare in the north of the country, which is relatively free of the Taliban-linked violence that sees regular violence in the south.
The Islamist Taliban movement launched an insurgency after it was removed from government in November 2001 by a coalition led by the United States.
Around 45 civilian aid workers have been killed in Afghanistan since 2002, many of them in violence linked to the growing insurgency.
{{/usCountry}}Around 45 civilian aid workers have been killed in Afghanistan since 2002, many of them in violence linked to the growing insurgency.
{{/usCountry}}ActionAid, an international aid organisation set up to fight poverty, has been working in Afghanistan since 2002.