Tehran, Iran (CNN) -- Amir Mirzaie Hekmati, an American sentenced to death in Iran for espionage, has 20 days to appeal his case, according to Iranian law.
"If the sentence is appealed, then the Court of Appeals will hear the case. If not, then the sentence is final," judiciary spokesman Mohseni Ejeie said, according to the semi-official Iranian Student News Agency. The statement was the first by a judiciary official, regarding the trail and the sentence.
Hekmati's family has hired a high-profile lawyer with success in negotiating with Tehran to seek his release.
"We're prepared to open up a line of communication with the government," attorney Pierre Prosper said. "Our hope is that they will talk with us."
The goal is to remove the case from the political realm.
"This case is entrapped in an intense political environment," he said.
Prosper is a former ambassador-at-large for war crimes under the Bush administration and a prosecutor for the Rwanda tribunal at The Hague. He successfully negotiated with the Iranian government for last year's release of Reza Taghavi, an Iranian-American businessman detained for more than two years in Iran before being freed in 2010.
Prosper said his next step is to revive the contacts he dealt with in dealing with Reza Taghavi's case and try to meet directly with Iranian authorities.
Taghavi's release was the product of three trips by Prosper to Iran, meetings with Iranian officials in New York and Europe, and close to 300 e-mails with Iranian officials.
On Monday, the semi-official Fars news agency reported that a court had convicted Hekmati of "working for an enemy country," as well as membership in the CIA and "efforts to accuse Iran of involvement in terrorism."
Hekmati's family and the U.S. government deny the allegations.
The sentence came down five months after Hekmati's arrest.
In Flint, Michigan, where the Hekmatis live, the community rallied around them.
"It's horrible. I feel very bad for them," family friend Holly Ochodnicky told CNN affiliate WDIV-TV. "They're a great family. They're good people."
The news came amid rising tensions between the United States and Iran.
The International Atomic Energy Agency confirmed Monday that uranium enrichment has begun at a nuclear facility in northern Iran.
U.S. State Department strongly condemned the verdict.
"Allegations that Mr. Hekmati either worked for or was sent to Iran by the CIA are simply untrue," said department spokeswoman Victoria Nuland. "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 department urged Iran "to grant the Swiss protecting power immediate access to Mr. Hekmati, grant him access to legal counsel, and release him without delay. "
In the absence of diplomatic relations between the United States and Iran, Switzerland serves as the "protecting power" for U.S. interests in the country.
The complexities of the situation weren't lost at Mott Community College, where Hekmati attended and his father is a professor.
"Amir Hekmati is a pawn in this battle between two very powerful countries," school representative Michael Kelly also told WDIV. "Our concern here at the college is to protect the family. They are in a very difficult situation."
Hekmati's parents said they were "shocked and terrified" by the news.
"We believe that this verdict is the result of a process that was neither transparent nor fair," Behnaz Hekmati wrote in a statement on behalf of herself and her husband, Ali.
"Amir 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," the statement said.
"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. 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."
The statement also said Iran was denying that Amir is a U.S. citizen.
The family is working with a public relations firm and has launched a website -- FreeAmir.org.
"Maybe, and it's only a maybe, maybe there's a possibility that some international pressure might encourage the Iranians to issue a stay of clemency of some kind," political professor and family friend Paul Rozycki told CNN affiliate WEYI-TV.
Until now, Hekmati was represented by a government-appointed lawyer, despite his family's repeated efforts to hire a private lawyer for him.
Hekmati was arrested in August while visiting his grandmother and other relatives, his family in Michigan said last month.
The Hekmatis said their son served in the Marines from 2001 to 2005. Later, he started his own linguistics company and contracted his services to the military as well as civilian businesses.
His military contracts included cultural competency training. He worked with troops at military bases to promote understanding and positive communication with people of other cultures, his family said.
Iran's notorious secretive trials have been assailed by human rights groups and governments around the globe.
The U.S. State Department's annual human rights report on Iran says the court system is, in practice, "corrupt and subject to political influence." And while the country's constitution provides a defendant the right to a public trial, presumption of innocence, and a lawyer of his or her choice, "These rights were not respected in practice."
Hekmati is the latest in a series of Americans to face arrest in the country in recent years.
Three U.S. hikers, also accused of spying, were arrested in 2009 and ultimately released. Sarah Shourd was freed on medical grounds in 2010; Josh Fattal and Shane Bauer were freed in September 2011.
Journalist Roxana Saberi was arrested in January 2009 and convicted of espionage in a one-day trial that was closed to the public. She was freed in May that year.
Iranian-American Kian Tajbakhsh was among many people arrested in July 2009, amid post-election protests and a massive government crackdown. Exactly what he was convicted of was not clear.
In March the next year, he was allowed temporary release within the country to celebrate the Persian New Year. That temporary release was later extended, according to the website freekian09.org, which works for his release.
CNN's Ed Payne, Elise Labott and Shirzad Bozorgmehr contributed to this report.