Aid agencies have warned of a deteriorating situation in Afghanistan
An aid group has suspended its work in Afghanistan - after 20 years - following the killing of three female aid workers in an ambush near Kabul.
British-Canadian Dr Jacqueline Kirk, Canadian Shirley Case and Nicole Dial, a Trinidadian-American, were shot with their Afghan driver Mohammad Aimal.
The International Rescue Committee (IRC) workers had been driving to the capital from Gardez in the south-east.
Aid workers in Afghanistan are often targets, with staff abducted or killed.
In Wednesday's attack, a second Afghan driver was seriously injured when gunmen fired on the group in Logar province.
The group's vehicle had been clearly marked with the IRC logo, Logar deputy police chief Abdul Majid Latifi told the AFP news agency.
The aftermath of the ambush on the aid workers
The Taleban have claimed responsibility for the attack, describing the aid workers as foreign spies.
Spokesman Zabiullah Mujahid told the Associated Press that the group "were not working for the interests of Afghanistan".
The IRC said it was "stunned and profoundly saddened" by the deaths of the aid workers, who had been involved in children's and education programmes.
"Words are inadequate to express our sympathy for the families and loved ones of the victims and our devoted team of humanitarian aid workers in Afghanistan," said IRC president George Rupp.
A group of 100 aid agencies recently issued a statement warning of a "rapidly deteriorating" situation in some parts of the country.
Holly Richie, an independent development consultant based in Kabul, told the BBC there had already been a 50% reduction in aid agency coverage over the past four years.
The latest attack would "radically, radically impact on aid agencies operating in Afghanistan", she said.
Canadian Prime Minister Stephen Harper condemned the killings as "depraved".
"This cowardly attack on unarmed aid workers yet again shows the depravity of the Taleban and the bleak alternative that they represent," he said in a statement.
Mr Harper also confirmed Canada's commitment to Afghanistan, where 2,500 troops of its troops are deployed as part of Nato-led forces battling Taleban and other militants.