Story highlights NATO admits causing the deaths after an earlier denial that civilians were killed

An Afghan official says the victims were women gathering wood at night

ISAF has been working for years to tackle civilian casualties

NATO admitted that it had killed Afghan civilians in an airstrike early Sunday morning, hours after saying there was no evidence of civilian deaths.

"A number of Afghan civilians were unintentionally killed or injured during this mission," the coalition said in a statement accepting "full responsibility for this tragedy."

NATO's International Security Assistance Force "offers its sincerest regret to the families," the statement said.

The coalition first cast doubt on an Afghan official's assertion that eight women were killed and seven more wounded in a coalition airstrike Sunday morning in Laghman province.

As the day went on, ISAF changed its line, saying it was aware of the incident and the allegations.

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It finally admitted that the Afghan report was correct.

Afghan official Abdul Khaliq Husaine had said women normally go out to collect wood in the night, and that they came under attack in the early hours of Sunday morning.

The incident took place in the province's Alingar district.

Sarhadi Zwak, a provincial spokesman, also said civilians had been killed, and that the airstrike was carried out without coordination with Afghan officials.

Earlier, ISAF said it had been targeting "a large group of insurgents" in the province, east of the capital Kabul.

It identified the group of about 45 as hostile, and attacked with "precision munitions and direct fire," said spokesman James Graybeal.

The strikes "killed a large number of the insurgents and forced the group to depart," he said.

Taliban spokesman Zabiullah Mujahed said the strike killed more than 20 civilians, and condemned the attack. The Taliban frequently exaggerates death tolls.

Civilian casualties in the war between coalition forces and militants have generated grass-roots anger toward the combatants, and ISAF has been working for years to tackle the problem