Afghan President Hamid Karzai on Monday condemned the killing of 52 civilians by a rocket fired by NATO troops on Friday.

In a statement issued Monday evening, Karzai said the investigation by Afghan intelligence agency showed that a rocket fired by NATO forces on Friday hit a house in Sangin district, killing 52 civilians, including women and children.

Earlier Monday, Afghan government spokesman Siamak Heravi said NATO troops were fighting Taliban militants in Sangin district on Friday. A group of civilians jammed into a house to avoid the fighting, when a NATO rocket hit the house.

Early on Saturday locals in Sangin district said that more than 50 civilians including women and children were killed as NATO's aircrafts dropped bomb.

Abdul Ghafar, 60, who took four injured children of his family to Kandahar's Mir Wais hospital told Xinhua on Saturday that the incident occurred during battle between NATO-Afghan troops and Taliban insurgents.

He also added that members of six families gathered in a house in Regi village of Sangin district when came under the attacks from air and ground as a result between 50-60 people with majority of them civilians were killed.

Karzai on Sunday ordered concerned authorities to investigate the case.

Spokesman for Helmand's provincial administration Daud Ahmadi said earlier that investigation team had sent to the site of the incident to investigate the case and after completion of the investigation the exact figure of the casualties would be made public.

NATO forces on Saturday rejected the claim, saying no operation has been carried out in Sangin district. A NATO spokesman on Monday evening insisted that initial investigation showed there was no operation in Sangin district, but the troops are still checking about the incident.