KABUL — NATO was accused of killing eight women Sunday in an air strike, capping a black weekend in which six soldiers were shot dead by presumed Afghan colleagues and a Taliban assault caused unprecedented losses on one of the biggest military bases in the country.

The US-led International Security Assistance Force initially said an air strike targeted around 45 insurgents, but later expressed its sincerest condolences over "possible ISAF-caused civilian casualties" numbering five to eight.

Civilian casualties have strained relations 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 of Laghman province, east of Kabul, as women set off to collect fire wood, said Afghans.

"In this raid, eight women are killed and another eight women are wounded," provincial spokesman Sarhadi Zwak told AFP.

A crowd of 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 expressed sadness over the deaths and condemned the killing of eight women, and what his office said were seven other women wounded, ordering a delegation to travel to the area to investigate.

In Zabul province, part of the south where the 10-year Taliban insurgency is traditionally strongest, four NATO 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 Messers said the shooting happened at around 1:00 am (2030 GMT Saturday) 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 unit, which has also 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 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 at least 15 attackers dressed in US Army uniforms, 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 destroyed and six aircraft hangars also 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, its spokesmen told AFP the attack was to avenge the insult to the Prophet Mohammad.

"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 attack 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.