A grave error has been committed, and we have authorized our legal representatives to make direct contact with the Iranian authorities to find a solution to this misunderstanding.

WASHINGTON — The family of an American man sentenced to death in Iran for allegedly being a CIA agent said Monday he was visiting relatives there and not spying.

Behnaz Hekmati, mother of Amir Mirzaei Hekmati, said in an email to The Associated Press that she and her husband Ali are "shocked and terrified" that their son has been sentenced to death. The verdict is "the result of a process that was neither transparent nor fair," she said.

Iran charged that Hekmati received special training and had served at U.S. military bases in Iraq and Afghanistan before heading to Iran for an intelligence mission. A court convicted him of working with a hostile country, belonging to the CIA and trying to accuse Iran of involvement in terrorism, according to a state radio report Monday.

The 28-year-old former military translator was born in Arizona and graduated from high school in Michigan. His family is of Iranian origin, and Amir Hekmati claims dual citizenship. His father, Ali, a professor at a community college in Flint, Mich., has said his son was visiting his grandmothers in Iran.

The State Department demanded Hekmati's release anew Monday, while officials worked to confirm the details of his sentence and what could be done about it. The White House said the U.S. would work with its diplomatic partners "to convey our condemnation to the Iranian government."

Swiss diplomats, acting on behalf of the United States because Washington and Tehran don't have diplomatic relations, have tried unsuccessfully to gain consular access to Hekmati. Iran doesn't recognize dual citizenship and considers Americans of Iranian origin to be solely citizens of the Islamic republic.

"We are working through the Swiss protecting powers in Tehran to confirm reports in the Iranian press that Mr. Hekmati has been sentenced to death by an Iranian court," State Department spokeswoman Victoria Nuland said.

"If true, we strongly condemn this verdict," she said. "Allegations that Mr. Hekmati either worked for, or was sent to Iran by the CIA are simply untrue. The Iranian regime has a history of falsely accusing people of being spies, of eliciting forced confessions, and of holding innocent Americans for political reasons."

The State Department has warned U.S. citizens of Iranian background to avoid visiting the country because of "the risk of being targeted by authorities."

"Iranian authorities have detained and harassed U.S. citizens of Iranian origin," the department says in its Iran travel warning.

The sentence against Hekmati comes amid heightened U.S.-Iranian tensions.

The Obama administration is initiating new sanctions against Iran over its disputed nuclear enrichment program, specifically targeting the regime's central bank and its ability to sell petroleum abroad. Iran has responded with warnings to American vessels against entering the Strait of Hormuz, the strategic waterway that carries to market much of the oil pumped in the Middle East.

Nuland urged Iran's government to release Hekmati without delay. But American officials are concerned his case may become a political tool for the Iranian government.

Having imposed the worst possible sentence immediately, Iran could now seek to drag the case out. In past cases Iran has held out the possibility of releasing American prisoners on humanitarian grounds, presumably in the hopes of gaining a counter-concession from Washington. September's release of a pair of American hikers held captive by Iran for two years is the most recent example.

In the email, Hekmati's mother said her son did not engage in any acts of spying, or "'fighting against God,' as the convicting judge has claimed in his sentence. Amir is not a criminal. His very life is being exploited for political gain."

"A grave error has been committed, and we have authorized our legal representatives to make direct contact with the Iranian authorities to find a solution to this misunderstanding," the family statement said. "We pray that Iran will show compassion and not murder our son, Amir, a natural born American citizen, who was visiting Iran and his relatives for the first time."