KABUL – The NATO-led international force in Afghanistan rejected on Friday reports from Afghan officials that it killed more than 50 civilians in air strikes the previous day in the west of the country.

At least four men were killed in the strikes, a spokesman for the regional police command had said on Thursday. Witnesses said 17 people were also wounded.

But other reports, by Shindand District Chief Mullah Lal Mohammad and a tribal elder, Haji Zalmai, said that more than 50 civilians had been killed in the strikes in the villages of Farmakan and Bakhtabad in the western province of Herat.

'ISAF has thoroughly investigated and rejects claims that ISAF forces killed more than 50 civilians in the Shindand area,' the International Security Assistance Force said in a statement.

'Our extensive investigation reveals that the closest airstrikes carried out were 13 km to the South East of these villages. ISAF therefore rejects these claims as baseless.'

In a statement released on Thursday the U.S. military had said the raid was against 'high priority Taliban targets' and that two 'Taliban leaders' and a 'significant number of insurgents' were also killed. It said there was no evidence of any civilian casualties.

However, the U.S. military confirmed on Thursday that it had killed eight civilians in an air strike on Tuesday in the neighbouring province of Farah.

The U.S. military says it is also investigating reports by Afghan officials that around 60 civilians were killed in two separate air strikes by U.S.-led coalition forces this month in eastern Afghanistan.

The issue of civilian casualties is a highly sensitive one for the Western-backed government and undermines Afghan support for the presence of foreign forces who are fighting the Taliban-led insurgents in Afghanistan.

There has been a sharp rise in violence in Afghanistan this year, the bloodiest since U.S.-led and Afghan forces overthrew the hardline Taliban in the wake of the Sept. 11, 2001 attacks.

(Reporting from Kandahar by Ismail Sameem; Writing by Jonathon Burch; Editing by Alex Richardson)