An Iranian security court has held the first hearing in the closed trial of an American-Iranian reporter for The Washington Post who has been detained for more than 10 months.

Jason Rezaian is being tried in a Revolutionary Court on allegations of "espionage for the hostile government of the United States" and propaganda against the Islamic republic, charges that could send him to jail for up to six years.

Initial hearings in Iran usually see the prosecutor spell out charges.

Mr Rezaian, his wife Yeganeh Salehi and two photojournalists were detained on July 22 in Tehran.

All were later released except Mr Rezaian, who was born and spent most of his life in the US and holds both American and Iranian citizenship. Iran does not recognise other nationalities of its citizens.

US officials have repeatedly pressed Iran to release Mr Rezaian and other jailed Americans, including during talks on the sidelines of negotiations over Tehran's nuclear programme. Iran and world powers hope to reach a comprehensive agreement on the programme by the end of June.

The Washington Post has criticised Mr Rezaian's detention and the handling of the case. It said his mother and wife have been barred from attending the trial, and that requests for a visa for a senior editor to travel to Iran went unanswered.

"There is no justice in this system, not an ounce of it, and yet the fate of a good, innocent man hangs in the balance," Washington Post executive editor Martin Baron said.

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