IRNA quoted Tehran's chief prosecutor Abbas Jafari Dowlatabadi as saying the Americans' next court appearance is tentatively set for the summer session of the court, between June 22 and August 22.
He said officials "are hopeful that the final decision about the three Americans' case will be taken at that session." He did not elaborate.
The three Americans - Shane Bauer, Josh Fattal and Sarah Shourd - were detained in July 2009 along the Iran-Iraq border.
Bauer and Fattal remain in custody. Bauer's fiancee, Shourd, was released last year on $500,000 bail and has refused to return to Iran for trial. The three deny the allegations.
"We are hopeful that final decision about the three Americans' case to be taken in the session" set for the summer, he said, without hinting at what the decision might be.
The three were detained in July 2009 along the Iran-Iraq border. They deny the charges and claim they were only hiking in a scenic area of northern Iraq near the Iranian frontier.
The espionage trial had been scheduled to resume May 11, but Bauer and Fattal were not brought to court and the session was called off. Iranian officials offered no explanation at the time.
Dowlatabadi said Tuesday that the delay was the result of lack of coordination. He said the prisoners have had "the best conditions" in jail.
Masoud Shafiei, lawyer for the three, told The Associated Press on Tuesday that he expects them to be cleared.
He said, "There is no room for the charge if spying in their case. On illegal entry, it was not fault of my clients, if it happened."
The U.S. government has often appealed for their release, insisting that they have done no wrong.
In October, U.S. Secretary of State Hillary Rodham Clinton repeated the request. "There are many areas where we need to be discussing matters between the United States and Iran that are of great significance to not only our two countries but the world," she said then. "And it's unfortunate that Iran would be holding ... two young men who should be released and returned to their families."
Shafiei said he had no access to his clients in recent months.
In May, relatives of the two men said they called their families by telephone. It was their such first phone call since Nov. 27.
