NATO forces in southern Afghanistan bombed a civilian convoy, killing 27 people including women and children and injuring many more, Afghan officials said.
The airstrike in a remote part of Oruzgan province yesterday capped a bloody week for Afghan civilians that has seen some 60 innocent people killed by NATO weapons.
Afghanistan's cabinet called the attack "unjustifiable" and condemned the raid "in the strongest terms possible".
Officials said three vehicles were bombed, killing at least 27 people, including four women and one child, while at least 12 others were injured. The death toll had earlier been put at 33.
The cars were traveling between Kandahar and Daikundi, in Afghanistan's central highlands, when NATO and Afghan forces mistook them for insurgents.
NATO's International Security Assistance Force (ISAF) said troops on the ground thought the civilians were militants "en route to attack a joint Afghan-Isaf unit" but they later confirmed that there were women and children at the scene and launched an investigation.
The local governor and the interior minister said all of the victims were civilians.
US General Stanley McChrystal, the commander of NATO forces in Afghanistan said he was "extremely saddened".
"I have made it clear to our forces that we are here to protect the Afghan people, and inadvertently killing or injuring civilians undermines their trust and confidence in our mission," he said in a statement yesterday. "We will re-double our efforts to regain that trust."
NATO has been criticized in the past for relying on shoddy intelligence and calling in airstrikes when there is no immediate need.
General McChrystal has urged troops to refrain from using heavy weapons, by showing what he calls "courageous restraint". On Saturday President Karzai repeated calls for the coalition to eliminate civilian casualties.
"We need to reach the point where there are no civilian casualties," Mr Karzai said. "Our effort and our criticism will continue until we reach that goal."
But the last seven days have been anything but peaceful. Last Sunday at least nine civilians were killed when troops involved in Helmand hit a compound with a volley of rockets, during Operation Moshtarak.
On Monday NATO and Afghan forces mistakenly killed five men and injured two others in Kandahar province after deciding that they had been planting a roadside bomb. "The joint patrol called for an airstrike," Isaf said in a statement. "Following the strike, the Afghan-ISAF patrol approached the scene and determined the individuals had not been emplacing an IED."
On Thursday, an airstrike in northern Kunduz province missed insurgents and killed seven policemen while on Friday a man carrying a box was shot and killed in Nad-e Ali. "The man dropped the box, turned and ran away from the patrol, and then for an unknown reason turned and ran toward the patrol at which time they shot and killed him," NATO said in a statement. "After a search of the individual it was determined the box, which appeared to be filled with IED-making materials, was not an IED."
In December NATO was accused of killing 10 civilians, including eight schoolchildren, in Narang district in Kunar. NATO claimed they were part of a bomb-making cell.
Yesterday's civilian deaths come as a further blow to the Western effort in Afghanistan after the Dutch Prime Minister conceded that he could not prevent his forces being pulled out this year due to the collapse of his Government.
Jan Peter Balkenende lost the argument over extending the deployment at a 16-hour Cabinet session, in the first big reversal for the recently appointed NATO leader, Anders Fogh Rasmussen, who had publicly requested a continued Dutch commitment.
"Our task as the lead nation [in Uruzgan province] ends in August," Mr Balkenende said. After a three-month draw-down, the Dutch will be completely out of Afghanistan by the end of the year.
There are concerns that other countries where public opinion is turning against the Afghan campaign could follow, notably Canada, which has had the biggest proportional casualty rate and is committed to withdrawing its 2,800 troops by the end of next year.
Another concern is the continued presence of 1,000 Australian troops. The Canberra Government has repeatedly refused to take over the lead role in Uruzgan if Holland leaves, demanding that a big NATO power provide the main share of troop numbers.
Just as important is the impression that European countries are struggling to find their share of the 10,000 extra troops requested by General McChrystal to join 30,000 extra US troops in Afghanistan, with France ruling out more forces and a fierce debate in Germany.
The Times understands that the Dutch forces in Uruzgan will be replaced by US troops, diverting them from the surge operation against the Taliban.