The Taliban have vowed revenge against the U.S. after at least one American soldier shot to death 16 civilians in southern Afghanistan and burned their bodies.
The militant group said in a statement posted on their website Monday that "American savages" committed the "blood-soaked and inhumane crime" in Panjwai district.
The U.S. has said the shootings before dawn Sunday in two villages were carried out by a single American soldier, who is now in custody.
But Afghans have expressed doubt that a single soldier could have carried out the shootings in houses over a mile apart.
The Taliban claimed responsibility for several attacks last month that the group said were in retaliation for the Americans burning Qurans.
Afghan President Hamid Karzai puts the death toll from an overnight shooting rampage in southern Kandahar at 16.
An American soldier is being blamed. NATO says he's been detained.
The deputy commander of NATO forces in Afghanistan says he's "dismayed" by the incident. Lt. Gen. Adrian Bradshaw says he can't explain the motivation for what he calls "callous acts," but adds they were "in no way" authorized.
In a statement, Karzai furiously demanded an explanation and noted his repeated demands that U.S. forces stop killing civilians. He calls the incident in Kandahar "an assassination" of innocent civilians that cannot be forgiven.
Afghan officials say the attacks took place in two villages not far from a U.S. base. One villager says the American entered at least three houses and opened fire.
Nine children and three women were among the dead.
The killings follow weeks of violent protests and attacks triggered by the burning of Muslim holy books at another U.S. base in Afghanistan.
A U.S. service member walked out of his base in southern Afghanistan before dawn Sunday and started shooting Afghan civilians, Afghan and NATO officials said. There were widely varying reports of casualties.
People were killed in the shooting spree in Kandahar province, Gov. Tooryalai Wesa said, though he did not provide numbers.
"The incident happened. There are some people killed, some wounded. But I don't have the details," Wesa said in a phone interview.
Helicopters were circling overhead at Alkozai village in Panjwai district as a delegation from the governor's office arrived to determine exactly what happened, but details were still sketchy.
A resident of Alkozai, where the shootings took place, told an Associated Press reporter that 16 people were killed as the U.S. service member went into three different houses and started shooting. The villager, Abdul Baqi, said he had not seen the bodies himself, but had talked to the family members of the dead.
"When it was happening in the middle of the night we were inside our houses. I heard gunshots and then silence and then gunshots again," Baqi said.
NATO spokesman Justin Brockhoff said a U.S. service member had been detained as the alleged shooter and that the coalition had reports of "multiple wounded" but none killed. The wounded were evacuated to NATO medical facilities, he said.
The service member was being held at a NATO base and U.S. forces are investigating the shooting in cooperation with Afghan authorities, Brockhoff said. He said it was not clear if the alleged shooter knew the victims.
"This is a deeply regrettable incident and we extend our thoughts and concerns to the families involved," NATO said in a statement.
There were reports of protests in Panjwai following the shooting and the U.S. embassy warned travelers in Kandahar province to "exercise caution."
The shooting comes after weeks of tense relations between U.S. forces and their Afghan hosts following the burning of Qurans and other religious materials at an American base. Though U.S. officials apologized and said the burning was an accident, the incident sparked violent protests and attacks that killed some 30 people. Six U.S. troops have been killed in attacks by their Afghan colleagues since the Quran burnings came to light.
In the capital, meanwhile, Afghan President Hamid Karzai said the government still expects to sign a strategic partnership agreement with the United States by the time a NATO summit convenes in Chicago in May. The agreement would formalize the U.S.-Afghan relationship and the role of U.S. forces in Afghanistan after NATO's scheduled transfer of security responsibility to the Afghan government at the end of 2014.
But Karzai stressed the importance of foreign forces leaving Afghanistan to preserve the country's national sovereignty. Any international forces that remain after 2014 would have to operate under strict guidelines governing their responsibilities and when they could leave their bases, he said.
"We have a strong army and police, so it is to our benefit to have good relations with the international community, not have international troops in our country," Karzai said at a public event in Kabul.
The president has demanded that international forces stop night raids on the homes of suspected militants as a condition to signing the strategic partnership agreement. The raids have caused widespread anger among Afghans.
Also Sunday, a prominent Afghan women's rights activist said gunmen attacked her office in a western province in an apparent assassination attempt.
Malalai Joya, a former Afghan lawmaker and vocal critic of both the Taliban and of criminality in the Afghan government, said the attack on her office in Farah province was the sixth attempt on her life to date.
Armed men tried to storm the compound before dawn on Saturday, she said. The attackers did not get into the building but two of her guards were seriously injured and are currently in the hospital.
Joya said she was in Kabul at the time but had planned a trip to Farah soon and news of that may have leaked out. She said she believes the attackers thought she was in the building.