An operation by international forces in western Afghanistan on Friday killed 76 civilians, including 50 children and 19 women, the Afghan interior ministry said.
The US-led coalition confirmed it had carried out an operation, which included air strikes, in the area but said only 30 Taliban were killed, while the Afghan defence ministry said five civilians and 25 rebels had died.
It was impossible to independently verify what happened in volatile Shindand district in Herat province, but the conflicting reports highlight the difficulty in establishing facts in regular clashes between troops and rebels.
"Seventy-six people, all civilians and most of them women and children, were martyred during the operation by coalition forces in Shindand district of Herat province," the ministry said in a statement.
The dead were "19 women, seven men and the rest children all under 15 years of age," it said.
The ministry confirmed it would be one of the highest civilian deaths tolls in the battle to fight the extremist Taliban, who were ousted during a US-led invasion in 2001.
"The interior ministry, while expressing its profound regret because of this incident which happened by accident, has sent a delegation of 10 people to the area and more details will be announced once the investigation is completed," the statement said.
It said an unknown number of Afghan civilians were wounded, with some of them in a critical condition.
The police chief for western Afghanistan, Akramuddin Yawer, had also said 76 people were killed in the incident and 15 houses were destroyed in strikes.
"Taliban are included but their number is unknown," he said.
The coalition said 30 insurgents were killed in clashes and air strikes that followed an ambush on Afghan National Army (ANA) and coalition troops as they were going to arrest a Taliban commander.
"The ANA and coalition forces killed 30 insurgents," it said, adding a "known" Taliban commander was among the dead.
Two civilians were wounded. "No other civilian or friendly casualties were reported," the coalition said.
Five men were arrested and an arms cache consisting of Kalashnikov assault rifles, more than 4,000 rounds of ammunition and bomb-making materials, was discovered.
An Afghan army official from the area said meanwhile that only five civilians -- three women and two children -- had died.
"Planes bombed the area and in the result 25 Taliban were killed including two famous commanders," said defence ministry spokesman General Mohammad Zahir Azimi. "Unfortunately, five civilians were killed and one woman and a boy were wounded."
Military operations and insurgent attacks have increased in the summer with a Taliban-led insurgency growing steadily despite the efforts of nearly 70,000 international troops.