Three Western women aid workers and their Afghan driver were shot dead Wednesday by gunmen who fired numerous times into their vehicle near the capital Kabul, Afghan police and their organisation said, AFP reported.
The killings, claimed by the insurgent Taliban, are the deadliest in years involving international aid workers and come amid warnings about deteriorating security, said to be at its worst since the 2001 ouster of the Taliban regime.
The women were members of the International Rescue Committee, which has worked with refugees in Afghanistan for 25 years.
The women were named by the IRC on its website as British-Canadian Jacqueline Kirk, 40, of Outrement, Quebec, a dual citizen of Canada and Britain; Trinidadian-American Nicole Dial, 30, a dual citizen of Trinidad and the US; and Canadian Shirley Case, 30, of Williams Lake, British Columbia.
The driver was named as Mohammad Aimal, 25, from Kabul.
Another driver was critically wounded, the IRC said in a statement, adding it had suspended relief work in Afghanistan indefinitely.
The group was driving to the capital in a two-vehicle convoy when they came under attack near the town of Pul-i-Alam, about 50 kilometres ( 30 miles) south of Kabul, Logar province police chief Ghulam Mustafa said.
A car cut in front of their vehicles and then opened fire, he told AFP.
"Three females, foreign nationals, and an Afghan male have been killed," he told AFP. "Police went to the site and evacuated their bodies."
The bodies were kept in rough pine coffins in the main hospital in Pul-i-Alam before being transported back to Kabul mid-afternoon, an AFP photographer at the scene said.
"They were driving in a Land Cruiser with a clear IRC logo on it," Logar's deputy police chief Abdul Majid Latifi told AFP.
He said it appeared the attackers had broken the windows of the vehicle and shot them at close range.
"There were signs of about 10 bullets on the vehicle but more bullets on the body of the victims. They were hit by dozens of bullets," he said.
A spokesman for the Taliban, Zabihullah Mujahed, said men from his militia had ambushed a two-vehicle convoy in Logar transporting "military personnel, most of them female."
"We killed several of them... they were all military," he said.
The New York-headquartered IRC said in a statement it was "stunned and profoundly saddened by this tragic loss."
Two Afghan staffers of IRC were killed in an ambush in Logar a year ago. In a recent statement remembering the deaths, the organisation blamed "anti-government violence."
President Hamid Karzai condemned Wednesday's killing as "unforgiveable".
In a statement, he blamed "enemies of Afghan people who do not want the international community help the poverty-hit Afghan people."
The UN special representative in Afghanistan, Kai Eide, said it was "reprehensible that such selfless individuals working for the most vulnerable communities should be deliberately targeted in this way."
UN humanitarian chief John Holmes appealed for the protection of other workers in the region.
"Nothing can justify such an attack on people whose lives are devoted to helping the people of Afghanistan," he said in a statement.
"Humanitarian workers should be protected by the principles of neutrality and impartiality, and must not be targeted, as they appear to be at present in Afghanistan."
UN High Commissioner for Refugees Antonio Guterres conveyed "deep shock and sorrow".
Afghanistan's international aid community was also shocked.
"This is a senseless act of murder which is morally indefensible," said a senior foreign aid worker who asked not to be identified.
"This highlights the deterioration in security conditions, which are worse than at any point since 2001."
Aid groups warned this month about deteriorating security, saying 19 non-government workers had been killed in the first seven months of the year, more than all of 2007.
"Aid organisations and their staff have been subject to increasing attacks, threats and intimidation, by both insurgent and criminal groups," the Agency Coordinating Body for Afghan Relief said in a statement.
Threats were limiting relief work in the country, which is facing drought with soaring food prices affecting the most poor, it said.
In what is believed to be the previous most deadly attack on aid workers, three Europeans and two Afghans working with Medecins Sans Frontieres (Doctors Without Borders) were killed in 2004 in the western province of Badghis.
Last month two French aid workers were kidnapped from their guesthouse in central Afghanistan by a man said to be a former Taliban commander. They were freed after more than two weeks.
Afghan authorities reported Wednesday meanwhile that seven policemen had been killed in a series of bomb attacks linked to the insurgency.