An Iranian scientist, who returned home last week charging he had been held by US agents for more than a year, has said that they had pressed him to agree to be exchanged in a "spy" swap for three US hikers in custody in Tehran.
In a lengthy interview aired by state television late on Saturday, Mr Shahram Amiri claimed that the US agents had acknowledged that the three Americans, detained on the Iran-Iraq border in July last year, were indeed "spies".
Challenged by the interviewer about the agents' description of the trio, who have consistently maintained that they were on a hiking holiday, Mr Amiri insisted: "That is the term they used."
Washington has repeatedly called on Tehran to release Shane Bauer, 27, Sarah Shourd, 31, and Josh Fattal, 27, insisting that they were holidaymakers who had innocently strayed across an unmarked border.
US media have questioned whether the three were even in Iranian territory at the time of their arrest.
Iranian officials have raised the possibility of trying the trio for espionage, but no official charges have been announced, and the affair has become an added irritant to already tense US-Iranian relations.
Mr Amiri returned to Tehran on Thursday just over a year after he mysteriously disappeared from the Saudi city of Medina while on a pilgrimage.
He had resurfaced at the Iranian interests section in the Pakistani embassy in Washington maintaining that he had been kidnapped by US agents and held against his will.
Mr Amiri said in the interview that the "spy swap" offer emerged after US agents holding him discovered he had been in touch with Iranian agents while in the United States.
"They (US agents) wanted me to say that 'I was an Iranian intelligence agent infiltrating the CIA'", Amiri said.
"If I said this, they said I could be part of a spy exchange programme, whereby I could be handed over to Iran in return for the three American spies arrested near the Iraqi border."
In previous interviews Amiri has said he was kidnapped at gunpoint by two Farsi speaking agents of the US Central Intelligence Agency in Medina.
US officials have repeatedly denied that Amiri was abducted, insisting he was in the United States of his own free will while acknowledging that Washington "had been in contact with him" during his stay.