The trial of Washington Post reporter Jason Rezaian, who is jailed in Iran, started on May 26 behind closed doors.
Iran's official IRNA news agency reported that Rezaian's wife, Yeganeh Salehi, who is also a journalist, appeared in court alongside her husband and a female press photographer.
The trial is being held in Branch 15 of the Tehran revolutionary court, which usually hears political cases or those related to national security.
MizanOnline, a news agency linked to the judiciary, reported that the first session ended after about three hours.
The Washington Post said the trial would be "closed to the world," in its May 25 edition, and slammed the unjustified jailing of its correspondent.
"The shameful acts of injustice continue without end in the treatment of... Rezaian," the newspaper's executive director, Martin Baron, said.
"Now we learn his trial will be closed to the world. And so it will be closed to the scrutiny it fully deserves."
Iranian Judiciary spokesman Gholamhossein Mohseni-Ejeie, was quoted by the ISNA news agency May 25 saying Rezaian's lawyer and an interpreter would be present in court.
"I cannot reveal the details of the case, but the trial will take place tomorrow, and it will be up to the judge to decide whether the trial will be public or not," he said.
The Post's Tehran bureau chief has been in Iran's notorious Evin prison since his arrest in July and reportedly has lost 40 pounds. His attorney has said he was charged with espionage.
"I think the only reason you could possibly imagine that the trial would be closed would be to prevent people from seeing the lack of evidence," Ali Rezaian said.
"It's unlike the Iranian court system, Iranian government, to keep things private when they can go out and use propaganda against people."
Ali Rezaian said the family had hoped that Rezaian's wife, journalist Yeganeh Salehi, and his mother would be allowed to attend the trial.
Jason Rezaian, who is from Marin County, California, was arrested at his home in Tehran along with his wife.
Salehi was freed on bail but faces similar charges and will be tried separately, Baron said.
The Post has said he is accused of spying because he allegedly collected confidential information about domestic and foreign policy and handed it to "hostile governments."
Douglas Jehl, the Post's foreign editor, called the charges baseless.
"What Jason did was act as a journalist, which involves gathering information, verifying information, and ultimately publishing it," he told Reuters Television.
Iranian 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.
"There is no justice in this system, not an ounce of it, and yet the fate of a good, innocent man hangs in the balance," said the Post's Baron.
"Iran is making a statement about its values in its disgraceful treatment of our colleague, and it can only horrify the world community."
U.S. President Barack Obama has called the charges against Rezaian "vague" and pressed Iran to release all American detainees.
With reporting by Reuters, AFP, and the Washington Post