Washington Post reporter Jason Rezaian faces espionage charges in Iran. (Via Reuters)

President Obama vowed Saturday night that the United States would not rest until a Washington Post reporter imprisoned for nine months in Tehran is freed.

In a sober moment at the end of an otherwise lighthearted and jestful speech at the White House Correspondents’ Association dinner, Obama noted that journalists around the world are unjustly imprisoned for doing their work, including “our own Jason Rezaian,” who is The Post’s Tehran bureau chief.

“For nine months, Jason has been in prison for nothing more than writing about the hopes and fears of the Iranian people,” Obama said.

He noted that he had spoken with Rezaian’s brother, Ali, who was present at the dinner.

“I have told him personally that we will not rest until we bring him home to his family, safe and sound,” Obama said.

President Obama and other attendees of the 2015 White House correspondents' dinner call for release of Jason Rezaian, the Washington Post correspondent in Tehran, who has been in Iran’s Evin Prison since July 2014. (AP)

The president’s remarks were the most high profile of a growing chorus of calls on behalf of Rezaian, who faces espionage charges. Some Republican senators last week urged the administration to make freedom for Rezaian and three other Americans held or missing in Iran a condition for a nuclear agreement. The administration, however, has been reluctant to link their fates with the effort to block Iran’s ability to build nuclear weapons, which Tehran denies wanting to do.

Rezaian’s imprisonment was noted at the beginning of the dinner when Christi Parsons, president of the White House Correspondents’ Association, noted that Rezaian is charged with the crime of “collecting information about internal and foreign policy.”

“That is also known as practicing journalism,” she said.

Obama’s comments marked one of the few times the president has personally mentioned Rezaian. Last month, in a speech keyed to the Persian new year known as Nowruz, he called on Iran to free Rezaian and the other Americans.

Secretary of State John F. Kerry has repeatedly brought up Rezaian and the other Americans during months of nuclear negotiations. Iran’s foreign minister, Mohammad Javad Zarif, has deflected questions about Rezaian, saying it is a judicial matter.

Rezaian, 39, has suffered health problems and bouts of depression since he was arrested last July 22, along with his journalist wife, Yeganeh Salehi. She was later released on bail, but Rezaian’s multiple requests for bail have been denied. Their case was assigned to the Revolutionary Court, the venue for national security cases. A judge known for imposing extremely harsh sentences, including the death penalty for anti-government protesters, will hear the case.

Though the court has never publicly revealed the charges against Rezaian, his lawyer has said he is accused of espionage and three other serious crimes against the state that she said stemmed from inquiries and contacts he made as a journalist. No trial date has been set, but his family has been told it may begin soon.

Jason Rezaian’s journey has taken him from a childhood in San Francisco to his father’s native Iran. At 37, he became the Washington Post correspondent in Tehran. In July 2014, he was thrown into Iran’s Evin Prison, where he remains. This is his story. (This video has been updated to reflect recent developments in the Rezaian case.) (Jorge Ribas/The Washington Post)

Ali Rezaian said he was grateful Obama mentioned the journalist at the dinner and said he hoped it would “shine light on his case and help to bring him home.”

In a statement, Rezaian called on Iran’s Supreme Leader, Ayatollah Ali Khamenei, to review his brother’s case and explain why the judge who approved his temporary detention order has been assigned to hear the case.

“Iran's laws on all these issues are clear, but through deception and obfuscation, Jason’s captors have convinced the Iranian government to permit their continued illegal detention of an innocent man,” said Rezaian, who was introduced at the dinner as a “tireless advocate” for his brother.

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