More than 50 non-combatants were killed by NATO troops in the troubled Helmand province in south Afghanistan on Friday, a spokesman to Presidential Palace said on Monday.

"Fifty-two civilians were killed in Sangin district on Friday as NATO forces fired a rocket," Siamak Heravi told Xinhua.

However, he did not give more details, saying a statement would be released in this regard.

Early on Saturday locals in Sangin district said that more than 50 civilians including women and children were killed as NATO's aircraft 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 a battle between NATO-Afghan troops and Taliban insurgents.

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

President Hamid Karzai on Sunday ordered concerned authorities to investigate the case.

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

NATO forces on Saturday rejected the claim, saying no operation has been carried out in Sangin district.