Relatives of 16 Afghan civilians killed by a US soldier on Sunday have demanded answers from President Hamid Karzai.
"We don't care about money we want justice," one villager from Kandahar province told him in Kabul.
Some of the villagers also said there had been more than one gunman, a claim that has repeatedly contradicted the official version since Sunday.
The soldier accused of the killings has been flown out of Afghanistan and is expected to face trial in the US.
Meanwhile, a Nato helicopter carrying Turkish troops has crashed into a house on the outskirts of the capital Kabul, killing at least 12 soldiers and two children on the ground.
The death toll is the heaviest single loss of life so far for Turkish troops in Afghanistan, of whom there are currently more than 1,800.
Police told the BBC a technical fault was to blame.
Sunday's shootings have placed new strains on the US in Afghanistan.
The Taliban called off peace talks in the wake of the deadly rampage - in which men, women and children were shot and killed at close range - although they made no mention of the massacre in the statement.
However, the US later stressed it remained committed to Afghan reconciliation despite the move by the Taliban.
Mr Karzai has also told the US that it must pull back its troops from village areas and allow Afghan security forces to take the lead, in an effort to reduce civilian deaths.
President Karzai listened as surviving family members from the Kandahar massacre gave their versions of the murders during a meeting in a grand hall in the presidential palace.
Some said only one killer had been involved, others that many US soldiers had carried out the attack in the early hours of Sunday. The dead included nine children.
"Why did this happen?" demanded one man who lost nine members of his family. "Do you have answers, Mr President?"
"No, I do not," responded a tired-looking Mr Karzai.
The president described US co-operation over the massacre as poor, reports say.
He also told villagers he would take up their claims that more than one soldier had killed the villagers.
The soldier accused of the killings is at a US base in Kuwait and is expected to be taken to the US, possibly on Friday.
Afghans had demanded he face justice in their country.
Earlier some of the first details about him emerged.
US lawyer John Henry Browne said the soldier - who has not been named - had received body and brain injuries while serving in Iraq and was unhappy about going for another tour of duty.
Speaking in Seattle, where the accused soldier is based at Joint Base Lewis-McChord, Mr Browne denied reports that the accused had problems either with alcohol or his marriage.