Jason Rezaian, Washington Post reporter, charged by Iran

Jason Rezaian has been the Washington Post's Iran correspondent since 2012

A Washington Post reporter who has been detained in Iran for more than four months has been formally charged.

However the nature of the charges was not clear to those in the Tehran court, the Washington Post reported.

Iranian-US citizen Jason Rezaian, 38, and his Iranian wife Yeganeh Salehi, were taken into custody in July.

Western news organisations, including the BBC, have difficulty operating in Iran, with journalists facing detention and surveillance.

The Post, quoting a source close to the case, said that Mr Rezaian spent about 10 hours in court on Saturday while his case was reviewed by a judge.

Mr Rezaian signed a document that said he understood he was being charged, the source added.

Washington Post Executive Editor Martin Baron expressed anger at Mr Rezaian's continued detention.

'Allegations baseless'

"We are dismayed and outraged by reports that Jason Rezaian, the Post's correspondent in Iran, has now been charged with unspecified crimes," he said in a statement.

"The Iranian government has never explained why Jason was detained or why he has been held for more than four months without access to a lawyer.

"Jason is an American citizen who was acting as a fully accredited journalist. If he has indeed been charged, we know that any fair legal proceeding would quickly determine that any allegations against him are baseless."

Yeganeh Salehi, also a journalist, was released on bail in October.

Authorities in Iran frequently detain or harass journalists working for Western news organisations, and westerners with dual citizenship are often targets.

Iran-based family members of BBC journalists have been questioned by intelligence services, and authorities have tried to intimidate London-based BBC Persian staff.