Last Updated May 26, 2015 6:00 AM EDT
TEHRAN, Iran -- The closed trial of an American-Iranian reporter for the Washington Post detained in Iran for more than 10 months got underway Tuesday in a court used to hear security cases.
Iran's official IRNA news agency said the trial of Jason Rezaian began in a Revolutionary Court, saying he had been charged with espionage and propaganda against the Islamic republic.
Tuesday's hearing didn't last long, with official media reporting it had ended after just several hours. It wasn't immediately clear when the next hearing would take place, and officials didn't give any details of what had happened in the court on Tuesday.
Rezaian, his wife Yeganeh Salehi and two photojournalists were detained on July 22 in Tehran. All were later released except Rezaian, who was born and spent most of his life in the United States, and who holds both American and Iranian citizenship.
U.S. officials and the Washington Post have repeatedly pressed for the release of Rezaian and two other Americans jailed in Iran.
Washington Post executive editor Martin Baron told CBS News correspondent Margaret Brennan the charges against Rezaian are "completely preposterous," and he fears the trial will not be fair.
"He was put into solitary confinement for many months, under very harsh conditions in the worst prison in Iran," Baron told CBS News. "He's only been able to meet with his lawyer for an hour and a half."
"While we still retain hope, we don't have a lot of confidence," Baron added.
Rezaian's mother Mary traveled to Tehran in the hope of being by her son's side for the trial, but the head of the Revolutionary Court -- a hardliner known within the country as the "judge of death" -- barred any members of the public from attending the proceedings.
Ali Rezaian told CBS News that Rezaian's mother and wife, Salehi, went to the court and waited all day Tuesday, but were not allowed into the session.
Mary was only allowed to meet with Jason for an hour last week.
"He was angry," Rezaian's brother Ali told CBS News. "Not at her, obviously, but at the governments -- both the United States government and the Iranian government. He definitely feels like he's a pawn; that he's in the middle of this situation and nobody's pushing hard enough to get him out."
Secretary of State John Kerry has lobbied for Rezaian's release personally on the sidelines of the ongoing nuclear negotiations with Tehran, and last month, President Obama promised action.
"We remember the journalists unjustly imprisoned around the world, including our own Jason Rezaian," Mr. Obama said at the White House Correspondents Dinner. "Jason's brother Ali is here tonight and I have told him personally we will not rest until we bring him home to his family, safe and sound."
But so far, says Brennan, the pressure has not made a difference.
"You know, I don't really do politics, but what I will say is that Jason is my brother. If he's not out, none of us have done enough," Ali told CBS News.