Iran says it has new evidence to show that one of its scientists was abducted by the United States last year.
The foreign ministry says it given documents relating to the case to the Swiss embassy.
The BBC reports the contents of the documents, have not been disclosed.
Shahram Amiri, who disappeared during a pilgrimage in Saudi Arabia a year ago, is believed to be in the United States.
Three videos purportedly of him emerged recently - one saying he had been kidnapped, the other that he was free.
The US has strenuously denied abducting Mr Amiri, but ABC News reported in March that the scientist had defected and was helping the CIA compile intelligence on Iran's nuclear weapons programme.
The State Department has refused to say whether he is in the United States.
There has been no official comment from the Swiss embassy.