An Iranian diplomat kidnapped in Iraq has appeared before journalists in Tehran, saying that a US official was present while his captors tortured him.
Medical staff stayed with Mr Sharafi during the press conference
Jalal Sharafi was brought to the news conference in a wheelchair flanked by nurses, a week after his release.
The second secretary at Iran's Baghdad embassy gave a detailed account of beatings and interrogations, including being whipped on his feet with cables.
The US has denied any involvement in Mr Sharafi's abduction.
He was released last Tuesday, a day before the Iranian government set free 15 British naval personnel it accused of illegally entering its waters, but no link has been confirmed between the two cases.
He was abducted in February and held for 57 days.
Looking thin and weak at the press conference, Mr Sharafi said his captors had shown him identity cards from the Iraq Ministry of Defence.
He said an American official had been present when he was tortured on his feet with what felt like an electric drill.
"When I regained consciousness, the person who came to me clearly introduced himself as an American and he could speak," Mr Sharafi told the BBC.
"But since I didn't speak English, I was using an Arabic translator," he said.
"At different stages, he told me this man had connections to the US embassy and was directly responsible for me."
A psychiatrist at the press conference told journalists that Mr Sharafi was continually reliving the trauma of his torture and had been badly affected by sleep deprivation, solitary confinement and a mock execution.
Earlier on Wednesday, a Red Cross official in Iran confirmed he had seen marks on Mr Sharafi's feet, legs, back and nose.
But Peter Stoeker said he was unable to say if the scars were result of torture.
The BBC's Tehran correspondent, Frances Harrison, says there were visible scars on Mr Sharafi's feet and ankles.
But, she says, it is far from clear who was holding him.
Last week, a White House spokesman denied any involvement in Mr Sharafi's abduction.
Gordon Johndroe dismissed the claims, accusing Iran's government of "trying to deflect attention away from its own unacceptable actions".
An unnamed US intelligence official also denied any claims of abuse, saying: "The CIA does not conduct or condone torture."