Three Americans have been sentenced to up to 10 years in jail after being found guilty by an Afghan court on charges including torture, running a private prison and illegal detention.
Jonathan "Jack" Idema, a former US Green Beret, was arrested in July along with another ex-serviceman, Brent Bennett, and documentary film-maker Edward Caraballo.
They had denied the charges and insisted they were in Afghanistan with US and Afghan government sanction to help track down al-Qaeda and Taliban extremists.
"I apologise that we tried to save these people," Idema told reporters immediately after the verdict.
"We should have let the Taliban murder every ... one of them," he said bitterly.
Idema and Bennett were each sentenced to 10 years in jail and Caraballo to eight.
Four Afghan co-defendants received sentences ranging from one to five years.
Mr John Edwards Tiffany, a lawyer for Idema, said they planned to appeal.
"Justice was not served today," Mr Tiffany said.
"I blame the US government, the Bush administration and the Afghan legal system, which is not anywhere near where it needs to be."
Idema told the court earlier that he had been issued with a passport by a special US agency that he declined to name and had a visa for Afghanistan similar to those given to special forces operatives.
Speaking under an oath he swore on the Koran, to applause from the gallery, Idema insisted he had been operating with official US and Afghan sanction.
"I swear in the name of Allah to tell the truth and nothing but the truth," he said.
He did not give details on why he thought the FBI had set him up, or what their motive might be.
Other media have reported that Idema saw himself as a bounty hunter, and was after the fortune US authorities have placed on Osama bin Laden's head.