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Nine children have been killed in a NATO air raid in Afghanistan's Kunar province. They were out collecting firewood on Tuesday when they were struck down in the Pech valley area.

Military officials attributed the incident to faulty communication when troops responded to an attack on a NATO base.

General David Petraeus, the international forces commander, has personally apologised to Hamid Karzai, the Afghan president, for the deaths.

Speaking over a secure video conference link on Wednesday, Karzai told Barack Obama, the US president, that civilian casualties are a serious problem that needs to be better addressed by the US-led forces.

Civilian casualties have long been a source of friction between the NATO force and Karzai, who condemned the Kunar incident, saying the victims were "innocent children who were collecting firewood for their families during this cold winter".

Afghan officials say as many as 65 civilians were killed in another air raid in February, claims that Petraeus have denied.

Al Jazeera's Sue Turton visited the village in Pech valley where the latest deaths occurred. Viewers may find some of the images disturbing.

Source: Al Jazeera