The US-led International Security Assistance Force initially said an air strike targeted about 45 insurgents, but later extended its “deepest regrets and sympathies” over “civilians who died or were injured” in Laghman province.
Such incidents have strained ties between the United States and Afghan President Hamid Karzai. In June, Isaf ordered an end to air strikes on homes, except as a last resort.
Sunday's attack came shortly before dawn, in Alingar district in the province east of Kabul, as women set off to collect fire wood, said a local official.
“In this raid, eight women are killed and another eight women are wounded,”provincial spokesman Sarhadi Zwak told AFP.
Tribesmen carried bodies to the provincial capital Mihtarlam, shouting “death to America, death to the Jews” outside the governor's office, an AFP reporter said.
Karzai condemned the killing of the women. Seven other women were wounded and a delegation had been ordered to travel to the remote area to investigate, his office said.
Isaf said that “a number of Afghan civilians were unintentionally killed or injured” in the strike done “solely with the intent of countering known insurgents”.
In Zabul province, part of the south where the 10-year Taliban insurgency is traditionally strongest, four US soldiers were shot dead and two wounded after being scrambled to help police repel an insurgent attack, officials said.
Details of the incident were murky.
Isaf spokesman Lieutenant Colonel Hagen Messer said the shooting happened at around 1:00 am but that it was still unclear whether the attacker “was an individual wearing a police uniform or definitely a policeman”.
“Three to four other policemen have disappeared. At the moment, we don't know where they have gone. We don't know if they fled fearing arrest or if they are linked to the Taliban,” a provincial official told AFP on condition of anonymity.
Taliban spokesman Yousuf Ahmadi denied that the militia planned the attack.
Sunday's deaths took to 51 the number of Western soldiers killed by Afghan colleagues in 36 incidents so far this year, in a growing trend that jeopardises Nato plans to train local forces to take over when they leave in 2014.
Two British soldiers were killed on Saturday in the southern province of Helmand by a man wearing the uniform of the Afghan Local Police (ALP).
US special forces have suspended training for about 1,000 recruits to the controversial ALP, which has been accused of corruption and violence towards civilians.
The killings came as Nato detailed unprecedented damage costing well into tens of millions of dollars in a sophisticated, well-coordinated attack on Camp Bastion, in Helmand, where Britain's Prince Harry is deployed.
Two US Marines were killed and several others wounded late Friday, when 15 attackers dressed as US soldiers, armed with guns, rockets and suicide vests stormed the airfield.
Six US AV-8B Harrier fighter jets were destroyed and two significantly damaged. Three coalition refuelling stations were also destroyed and six aircraft hangars damaged.
The militia claimed the assault was to avenge a US-made film deemed insulting to Islam that has sparked deadly riots across the Middle East and North Africa.
The British royal was never in danger, officials said. Although the Taliban have vowed to kill him, it told AFP the attack was to avenge the insult to the Prophet Mohammed.
“Prince Harry is there and if we'd caught him, we would have killed him but this attack was solidly in retaliation to the film,” Ahmadi reiterated Sunday.
But the assault raises major questions about how insurgents managed to penetrate such a massive logistics hub in the desert, home to 28,000 soldiers.
Speaking to AFP on condition of anonymity, a Western security official said it underscored how well trained, precise and coordinated the insurgents had become.
“It's a clear success for them. They managed to destroy a lot of aircraft in one of the most secure bases of the country,” the official said.
Nato is gradually withdrawing its 112,600 remaining troops. The Pentagon said last week that there are currently 77,000 US troops in Afghanistan.