The trial of an American journalist who has been held by Iranian authorities since July last year, will be closed to the public when it starts on Tuesday, his family has said.

Jason Rezaian, the Washington Post's bureau chief in Iran, will appear in a Revolutionary Court on Tuesday facing charges of espionage with only his attorney present, his brother Ali Rezaian said.

His mother and his wife, a journalist who also faces related charges, have been barred from attending the hearing.

"I think the only reason you could possibly imagine that the trial would be closed would be to prevent people from seeing the lack of evidence," Ali Rezaian told the Reuters news agency.

Jason Rezaian, who is an Iranian-American, was arrested along with his wife Yeganeh Salehi in July. Salehi was freed on bail in October.

Citing his lawyer, the Post said in April that Rezaian faces espionage charges for allegedly collecting confidential information about domestic and foreign policy and handing it to "hostile governments".

Martin Baron, the executive editor of the Post said there was 'not an ounce' of justice in the proceedings and the "fate of a good, innocent man hangs in the balance".

"Iran is making a statement about its values in its disgraceful treatment of our colleague, and it can only horrify the world community."

Rezaian, who has been detained for more than 10 months, was arrested at his home in the Iranian capital, Tehran, along with his wife and two Iranian-US friends who have not been named.

According to his family he has lost 40 pounds (18 kg) in weight while serving time at Tehran's notorious Evin prison.

Iranian Foreign Minister Mohammad Javad Zarif said in April that an intelligence operative, possibly linked to the US government, may have "taken advantage" of Rezaian.

US President Barack Obama has called the charges against Rezaian "vague" and pressed Iran to release all American detainees.

Source: Al Jazeera and agencies