At least 27 civilians died in a Nato air strike in southern Afghanistan, the Afghan cabinet says, revising downwards a prior statement that 33 were killed.
Nato said it hit a suspected insurgent convoy, but ground forces later found "a number of individuals killed and wounded", including women and children.
Sunday's attack, in Uruzgan province, was not part of a major Nato-led push in neighbouring Helmand province.
Civilian deaths in strikes have caused widespread resentment in Afghanistan.
By Chris Morris, BBC News, Kabul
One of the problems with this kind of incident is that it undermines the confidence of Afghan people in military operations right around the country.
This was not part of the big military operation going on further south in Helmand, Operation Moshtarak, but when people in Afghanistan read of civilians being killed by foreign military forces, there is anger right across the political and social spectrum.
People feel that is exactly the kind of incident that pushes people towards the Taliban - so just what Nato didn't want at this time.
Last year, Gen Stanley McChrystal, the Nato and US commander in Afghanistan, introduced much tougher rules of engagement in a bid to minimise such casualties.
The BBC's Chris Morris in Kabul says three vehicles on a road were hit by the strike on Sunday morning.
A Nato statement said it was thought the convoy contained Taliban insurgents on their way to attack Afghan and foreign military forces.
But the governor of Uruzgan province told the BBC all of the dead were civilians. He said the air strike took place in an area which is under Taliban control.
One of his spokesmen, Nisar Ahmad Khetab, said more than 40 people had been travelling in three vehicles when they were attacked.
He told the BBC Pashto service a delegation of elders had been sent to the area to investigate the deaths.
The Afghan government condemned the air strike, calling it "unjustifiable" and "a major obstacle" to effective counter-terrorism efforts.
In a revised statement, putting the death toll at 27, the Afghan cabinet said four women and one child were among those killed.
The cabinet also called on Nato "to closely co-ordinate and exercise maximum care before conducting any military operation so that any possible mistakes that may result in harming civilians... can be avoided".
Uruzgan province is where the Dutch mission to Afghanistan has been based since 2006, with nearly 2,000 service personnel.
The Dutch mission in Uruzgan is often praised for its developmental focus
Over the weekend, the Dutch government collapsed over disagreements in the governing coalition on extending deployments in Afghanistan beyond August this year.
Gen McChrystal has apologised to Afghan President Hamid Karzai and pledged a full investigation into the latest deaths.
The Nato commander said in a statement: "We are extremely saddened by the tragic loss of innocent lives.
"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.
"We will redouble our efforts to regain that trust."
Our correspondent says the strike was not linked to the Nato-led Operation Moshtarak, which is continuing in Helmand province, to the south of Uruzgan.
Last week, 12 civilians died in that offensive - whose name means "together" in Dari - when ground-launched rockets hit a home.
About 15,000 Nato and Afghan troops are involved in Moshtarak, now in its second week, and the largest operation since the Taliban were overthrown in 2001.
The head of US Central Command, Gen David Petraeus, said on Sunday the operation, part of a revised strategy for combating insurgents, would probably last up to 18 months.