Nato confirms Afghan raid deaths
Reports suggest at least 40 civilians died when a nomad camp was hit in Kandahar province's Panjwayi district.
A team of tribal and community elders will hold an inquiry, Afghan President Hamid Karzai's office said.
On Friday, at least 14 people died in Uruzgan province when their bus struck a roadside bomb, officials said.
It was not immediately clear what kind of the bomb caused the blast, or who planted it.
'Things go wrong'
Nato has said 48 Taleban fighters were killed in three raids in Kandahar province, but the Taleban have denied losing any men.
Local police and officials confirmed more than 40 people were killed in one of the Nato raids, Afghan interior ministry spokesman Zmarai Bashiry told the BBC.
Other local officials put the death toll at between 60 and 85.
One Afghan survivor told the BBC that those attacked were nomads who had been living outside a village in tents. Nato forces are the main component in Isaf, the international force deployed in Afghanistan.
A spokesman, Capt Andre Salloum, told AFP news agency:
"As soon as the battle ended, troops on the ground were able to identify 12 civilians."
Nato forces were working with the Afghan defence ministry to conduct further investigations, he added.
Another Nato spokesman, Mark Laity, said the troops sought to take maximum care to avoid civilian casualties.
"We've got tight rules of engagement but sometimes things go wrong..." he said.
"President Karzai quite understandably and correctly wants us to show maximum care - that's what we do."
Residents in Panjwayi say the bombing began on Tuesday and continued into the night.
Local people as well as district officials have described buildings destroyed by aerial bombings during the Eid al-Fitr festival marking the end of Ramadan.
"The planes came and were bombing 3am," one man said.
"And, in the morning, they started hitting our village with mortars and rockets. They didn't allow anybody to come to our help."
People told the BBC that the bodies of many locals had been pulled from the rubble of their homes and buried.
One local man who did not want to reveal his name said 20 members of his family had been killed and 10 injured.
He said that a nomad camp with no connection to the Taleban had been attacked:
"There are no Taleban here. We live outside the village in an open area in tents.
"Anyone can come here to see our homes and area. There are no Taleban here. We all are nomads living in tents.
"Each time they say that it was a mistake. They have destroyed us all in such mistakes. For God's sake, come and see our situation."
Karzai under pressure
President Karzai's office said his investigators would make suggestions on how to prevent such "unfortunate" incidents in future and ensure better co-ordination with foreign forces.
Mr Karzai has been under mounting pressure over civilian deaths and has urged foreign forces to exercise more caution.
Last week, up to 21 civilians were killed in two Nato operations in Kandahar and neighbouring Helmand province.
Hundreds of people have been killed in Afghanistan this year, the bloodiest since the Taleban were removed from power by US-led forces in 2001.The UN mission in Afghanistan has voiced serious concern about the Panjwayi deaths.