Saeed Abedini, a naturalized US citizen who converted to Christianity, was convicted of threatening Iran's national security over underground church activities a decade ago, according to the American Center for Law and Justice.
The Washington-based conservative legal advocacy group said Abedini and his lawyer were only allowed to attend one day of the trial, which began on January 21. There was no immediate confirmation of the verdict in Tehran.
"I am devastated for my husband and my family. We must now pursue every effort, turn every rock, and not stop until Saeed is safely on American soil," Naghmeh, his wife and mother of their two children, said in a statement.
She described as "psychological torture" an account from Iran at the start of the trial that Abedini would be released on bail.
Jordan Sekulow, executive director of the American Center for Law and Justice, said that a revolutionary court judge seen as close to Iran's clerical leadership handed down the verdict verbally, not in written form as required.
"Iran has not only abused its own laws, it has trampled on the fundamentals of human rights. We call on the citizens of the world to rise up in protest," he said.
Abedini's supporters said that he led underground churches in the early 2000s when such activity was largely tolerated during the reform-minded presidency of Mohammad Khatami.
After he resettled in the United States, Abedini was detained on a return trip to Iran in 2009 and let go following an agreement not to engage in underground religious activities, according to his family.
Naghmeh Abedini said that her husband complied with the 2009 agreement and had returned to Iran as part of efforts to build an orphanage.
State Department spokeswoman Victoria Nuland on Friday reiterated US concerns over the fairness of the trial.
"We condemn Iran's continued violation of the universal rights of freedom of religion, and we call on the Iranian authorities to respect Mr. Abedini's human rights and to release him," she said.
Iran's constitution following the 1979 Islamic revolution recognizes the rights of several religious minorities including Christians, but the regime has targeted converted former Muslims.