NATO airstrikes killed Afghan civilians in two provinces, local officials reported Monday, and the U.S.-led coalition said it plans an apology in one of the incidents.
An airstrike Friday killed six members of a family in the Sangin area of southern Helmand province, according to the provincial spokesman.
The strike was called in after insurgents attacked foreign and Afghan forces in the area, he said in a statement. Helmand's governor called the incident a mistake.
"At this point in the investigation, we are able to confirm the incident and will be formally apologizing in the next couple of days to the family," said Lt. Col. Stewart Upton, a spokesman for NATO's International Security Assistance Force (ISAF) in Afghanistan.
"We are deeply saddened by any civilian deaths, and particularly regret incidents where civilians are killed as a result of actions by ISAF."
There were conflicting accounts on the number of deaths in Bala Murghab district of northwestern Badghis province, where unconfirmed reports put the civilian deaths at 14.
Civilian deaths have long been a key source of tension between President Hamid Karzai and U.S.-led forces fighting the resurgent Taliban in Afghanistan.
The casualties are undermining efforts by Karzai, NATO and, in particular, the United States to win the hearts and minds of ordinary Afghans in the more than decade-long unpopular war.
Meanwhile, the Washington Post has learned that the United States has for several years been secretly releasing high-level detainees from a military prison in Afghanistan as part of negotiations with insurgent groups. It is apparently a bold effort to quell violence in the countryside but one that U.S. officials acknowledge poses substantial risks.
As the United States has unsuccessfully pursued a peace deal with the Taliban, the "strategic release" program has quietly served as a live diplomatic channel, allowing American officials to use prisoners as bargaining chips in restive provinces where military power has reached its limits.
But the releases are an inherent gamble: The freed detainees are often notorious fighters who would not be released under the traditional legal system for military prisoners in Afghanistan. They must promise to give up violence -- and U.S. officials warn them that if they are caught attacking American troops, they will be detained once again.
There are no absolute guarantees, however, and officials would not say whether those who have been released under the program have later returned to attack U.S. and Afghan forces once again.
"Everyone agrees they are guilty of what they have done and should remain in detention. Everyone agrees that these are bad guys. But the benefits outweigh the risks," said one U.S. official who, like others, discussed the issue with the Post on the condition of anonymity because of the sensitivity of the program.