Afghanistan's President, Hamid Karzai, has called on the United States to halt air strikes in his country, following attacks this week that Afghan officials said killed 147 people.
Farah Province deputy governor Yunus Rasooli said that residents of two villages hit this week by US warplanes had produced lists with the names of 147 people killed in the attacks.
"We demand an end to these operations ... an end to air strikes," Mr Karzai said in Washington.
The issue of civilian casualties is a source of great friction between the Afghan government and its US backers and the air strikes overshadowed a meeting between Mr Karzai and US President Barack Obama in Washington.
Mr Karzai told CNN that in the beginning of the seven-year-old war that ousted the Taliban, Afghans had tolerated air strikes, but mounting civilian deaths had eroded that understanding.
"We cannot justify in any manner, for whatever number of Taliban or for whatever number of significantly important terrorists, the accidental or otherwise loss of civilians," he said.
The Afghan leader said Mr Obama, in their White House summit this week, had expressed "sorrows and apologies" over the deaths in Farah province.
Violence this year has reached its highest level since the Taliban were ousted in late 2001, despite growing numbers of international troops. The US military plans to more than double its troop numbers in Afghanistan to 68,000 by the year's end.
If the civilian toll is confirmed it would be the deadliest single incident for non-combatants since US-led forces first started battling the Taliban in 2001.