Afghan police have arrested three Americans in Kabul (search), including one who was reportedly posing as a U.S. government or military employee.

U.S. and Afghan officials weren't saying much about the case.

A spokesman for international peacekeepers said only that he's "aware" of Afghan media reports that police also discovered an illegal jail allegedly run by the Americans, as well as guns and ammunition.

The U.S. Embassy identified one of the men as Jonathan Idema. But the military distanced itself from him in a statement that said Idema "does not represent the American government and we do not employ him."

He's believed to be a former Green Beret who supplied tapes of an alleged Al Qaeda (search) training camp to Western television networks in the wake of the war against the Taliban (search) in late 2001.