ANKARA, May 19 (Reuters) - The trial of jailed Iranian-American journalist Jason Rezaian will begin on May 26 at a court in Tehran, a judicial spokesman told a semi-official news agency on Tuesday, without elaborating on the charges against him.

The Washington Post journalist was arrested at his home in Tehran last July alongside his wife, journalist Yeganeh Salehi, and two Iranian-U.S. friends who have not been named.

The Washington Post said in April that Rezaian had been charged with espionage for allegedly collecting confidential information about domestic and foreign policy and handing it to "hostile governments", citing his lawyer.

Salehi was freed on bail while the couple were released under unknown conditions. The three have not been publicly charged.

"The trial session of Rezaian has been set by the branch 15 of the Revolutionary Court for Khordad 5 (May 26)," an unnamed official from the Judiciary Chief's office told Students News Agency ISNA.

Iran's Revolutionary Court handles cases related to serious political or security matters. It has not announced the charges or any other details on the pending trial. The semi-official Fars news agency said "the two others" detained with Rezaian would also be tried, without giving further details.

Neither Rezaian's lawyer nor the judiciary could be reached for comment.

The newspaper's executive editor, Martin Baron, has described the charges against Rezaian as "absurd, baseless and manufactured", while U.S. President Barack Obama called them "vague" and pressed Iran to release all American detainees.

Tehran and six major world powers, including the United States, are trying to meet a June 30 deadline for a final nuclear deal to end a decade-old standoff with the West.

Past cases of Westerners detained in Iran on accusations of espionage have put severe strain on Tehran's foreign relations. Three American hikers were held for over a year after being arrested on the border with Iraq in 2009.

Tehran also keeps a tight grip on the media. The Paris-based Reporters Without Borders says some 46 journalists and bloggers are jailed in Iran.

Rezaian, from Marin County, California, had been the Washington Post's bureau chief in Tehran since 2012. He has been held in Tehran's Evin prison, where dozens of political prisoners are held, since his arrest.

Iran's Foreign Minister Mohammad Javad Zarif said in April that an intelligence operative, possibly linked to the U.S. government, may have "taken advantage" of Rezaian.

Iran does not recognize dual citizenship. Iranian officials have repeatedly said that Rezaian's case was a judicial matter as opposed to politically motivated.

The Committee to Protect Journalists, a New York-based press freedom watchdog, has urged the Iranian authorities to drop the charges and release Rezaian.

(Writing by Parisa Hafezi; Editing by Raissa Kasolowsky) ((parisa.hafezi@thomsonreuters.com; +90 532 176 3452; Reuters Messaging: parisa.hafezi@thomsonreuters.com))

Keywords: IRAN USA/JOURNALIST