(CNN) -- The lawyer representing two U.S. hikers jailed in Iran has been denied a request to visit his clients on the eve of their trial, he told CNN on Saturday.
"I asked to see them before the trial, but the judge told me I couldn't," said Masoud Shafii.
The judge has granted Shafii permission to visit Shane Bauer and Josh Fattal for a few hours on Sunday prior to the start of the trial, Shafii said.
Bauer and Fattal, both 28, and Sarah Shourd, 32, were detained July 31, 2009, after they allegedly strayed across an unmarked border into Iran while hiking in Iraq's Kurdistan region. Prosecutors in Iran have charged them with spying and trespassing.
Human rights groups have condemned their arrests and their lengthy wait for a trial in Tehran's notorious Evin prison.
Last September, Iranian authorities released Shourd on bail because of a medical condition. Shourd has not responded to a court summons this week to return and stand trial on Sunday, Shafii said.
Iranian authorities said she will be tried in absentia if she doesn't appear in court.
Shafii told CNN he has reviewed his clients' case file and doesn't see any evidence of a crime.
"In my opinion, they haven't done anything wrong," Shafii said. "The accusation of spying is baseless, and if they trespassed into Iran, it wasn't their fault."
Shafii said the border area where the hikers are accused of trespassing is unmarked and anyone could unwittingly cross over into Iran.