A senior British Army officer has been arrested in Afghanistan for allegedly supplying sensitive civilian casualty figures to a human rights campaigner.
Lt Col Owen McNally, 48, was held in the war zone on suspicion of breaching the Official Secrets Act, it is understood.
The Ministry of Defence said the officer was being returned to the UK for questioning, where his case has been referred to the Metropolitan Police.
According to The Sun, Col McNally had access to the figures through his work for Nato's International Security Assistance Force, which is running military operations across the country.
American generals in the Afghan capital Kabul are reported to be furious about the allegations.
Last year campaign group Human Rights Watch said civilian deaths in Afghanistan from US and Nato air strikes nearly tripled to at least 1,633 between 2006 and 2007. The group said it used "the most conservative figures available".
The MoD said in a statement: "We can confirm that a British Army officer has been arrested in Afghanistan on suspicion of breaching the Official Secrets Act. He is being returned to the UK for questioning."
If charged, the officer will appear at the Old Bailey in London, which hears all such Official Secrets cases. He faces a maximum sentence of 14 years if convicted.
Col McNally joined the Army as a private in 1977 and worked his way up through the ranks before being commissioned as an officer in 1995. He is thought to be one of the Army's most senior former non-commissioned officers.
