An Iranian-American academic who has been detained in Tehran since May has said he expects to be freed soon.
Kian Tajbakhsh was interviewed by Iranian state TV while in detention
Kian Tajbakhsh, a planning consultant at the Soros Foundation's Open Society Institute, told reporters visiting Evin prison that he had been well treated.
Mr Tajbakhsh also said he had been told why he had been detained, but said he had not yet been formally charged.
In May, Iran said it had charged him with spying, acting against national security and conducting propaganda.
Mr Tajbakhsh was interviewed by Iranian state television two months later for a documentary which suggested there was a US-led plot to overthrow the Iranian government.
Journalists on a tour of the Evin prison in Tehran were given a surprise meeting with Mr Tajbakhsh.
"I do expect to be released soon. Exactly when, I do not know," he said.
"The conditions in prison are fine. I'm in a solitary cell, I have a television and a table. I have a private bathroom," he said. "I have weekly visits from my wife."
Mr Tajbakhsh then revealed that he had not yet been charged by Iranian judicial authorities, despite them claiming otherwise in March.
"There have been no formal charges with the case right now, my case is under investigation," he said.
"Of course, I've been told why I am being held but I prefer not to discuss issues with the case right now."
The academic insisted he was not guilty and said the interview on Iranian television had not been a confession.
The Open Society Institute, founded by George Soros, says it aims to shape public policy to promote democratic governance, human rights and economic, legal and social reform.
Mr Tajbakhsh was working in Tehran when he was arrested on 11 May.
He is one of four Iranian-Americans detained by Iranian authorities at the time on spying and propaganda charges.
Last week, Haleh Esfandiari and Parnaz Azima were released and allowed to leave Iran. Another academic, Ali Shakeri, is still being detained.