The US has denied claims made by an Iranian diplomat abducted in Iraq that he was tortured in captivity by people who included CIA agents.
Mr Sharafi (L) with Foreign Minister Mottaki on arrival back in Iran
A US spokesman said Jalal Sharafi's allegations of an American role in his detention were "theatrics" from the "Iranian propaganda machine".
Mr Sharafi, second secretary at the Iranian embassy in Baghdad, was freed last week. He was abducted in February.
He said CIA agents had interrogated him on his country's role in Iraq.
"The United States had nothing to do with Mr Sharafi's detention and we welcome his return to Iran," said Gordon Johndroe, a White House spokesman.
"This is just the latest theatrics of a government trying to deflect attention away from its own unacceptable actions," he said.
A US military spokesman in Baghdad also said that multinational forces had nothing to do with Mr Sharafi's kidnapping.
'Increased the torture'
The Iranian envoy told the Irna state news agency he was subjected to torture "day and night".
"I was kidnapped on a Baghdad street while shopping by officials who had Iraqi defence ministry ID cards and were riding in American forces vehicles," he said.
Mr Sharafi said he was taken from the Karrada district to a base near Baghdad airport and questioned in Arabic and English.
"The CIA officials' questions focused mainly on Iran's presence and influence in Iraq," he said.
"When faced with my responses on Iran's official ties with the Iraqi government they increased the torture."
Iran's Fars news agency said: "He showed reporters the marks left by torture on his body that are now being treated by doctors."
Mr Sharafi was freed on 3 April. Iraqi Foreign Minister Hoshiyar Zebari has said Baghdad does not know who held him.
Diplomatic tension remains high between Washington and Tehran over the detention by US forces of five Iranians in the Iraqi city of Irbil in January.
The US suspects them of aiding the Iraqi insurgency. Tehran says they have diplomatic status.
Iran this week released 15 UK sailors it had held for 13 days.