Iran's judiciary has indicted American journalist Jason Rezaian and sent his case to be tried in a hardline Revolutionary Court, the official IRNA news agency reported late on Wednesday.
Rezaian is the Washington Post's bureau chief in Tehran and holds Iranian-American dual citizenship. He was arrested five months ago along with his wife and two associates on unspecified charges. All but Rezaian have since been freed.
"Rezaian has been charged and his case has been forwarded to the Revolutionary Court," IRNA quoted Tehran Chief Prosecutor Abbas Jafari Dolatabadi as saying.
The charges against Rezaian were not specified, but Revolutionary Courts are tasked with trying major offenses such as espionage or blasphemy.
"We still do not know what charges the Iranian authorities have brought against our correspondent Jason Rezaian, but we hope the referral of his case to a Revolutionary Court represents a step forward toward Jason's prompt release," Martin Baron, executive editor of the Washington Post, said in a statement quoted on the paper's website.
"This step gives Iran's judiciary an opportunity to demonstrate its fairness and independence by determining that the charges are baseless," he added, calling on Iran to make the charges public and allow Rezaian access to a lawyer.
The United States has called for the release Rezaian and several other US citizens held in Iran, including former US Marine Amir Hekmati.
Iranian-American Hekmati was arrested in August 2011, his family says, and convicted of spying for the US Central Intelligence Agency, a charge his relatives and the US government deny.
Washington and Tehran severed relations after Iran's 1979 Islamic Revolution. The United States and other world powers are engaged in sensitive negotiations with Iran aimed at curbing its nuclear program in exchange for easing economic sanctions.