Roxana Saberi's Iranian-born father said his daughter was tricked into making incriminating statements by officials who told her they would free her if she did.
It was the first time Iran has found an American journalist guilty of spying, and it was unclear how it would affect recent overtures by the Obama administration for better relations and engagement with Washington's long-time adversary.
U.S. Secretary of State Hillary Rodham Clinton said she was “deeply disappointed” by the conviction.
Ms. Saberi, a 31-year-old dual American-Iranian citizen, was arrested in late January and initially accused of working without press credentials. But earlier this month, an Iranian judge levelled a far more serious allegation, charging her with spying for the United States.
She appeared before an Iranian court behind closed doors on Monday in an unusually swift one-day trial. Her lawyer was permitted to attend, but had declined to discuss any details.
The Fargo, North Dakota native had been living in Iran for six years and had worked as a freelance reporter for several news organizations including National Public Radio and the British Broadcasting Corp.
“Saberi has been sentenced to eight years in jail. I'll definitely appeal the verdict,” lawyer Abdolsamad Khorramshahi told The Associated Press.
Reza Saberi told NPR his daughter denied the incriminating statements she made when she realized she had been tricked but “apparently in the case they didn't consider her denial.”
He said his daughter was convicted Wednesday, but the court waited until Saturday to announce the verdict to the lawyers. He is in Iran but was not allowed into the courtroom to see his daughter, who he described as “quite depressed.”
North Dakota Senator Byron Dorgan called on the Iranian government to “show compassion” and release Ms. Saberi. “This is a shocking miscarriage of justice,” the Democrat said in a statement issued Saturday.
Ms. Clinton said in a statement the U.S. is working with Swiss diplomats in Iran to get details about the court's decision and to ensure Ms. Saberi's well-being. She said the U.S. will “vigorously raise our concerns” with the Iranian government.
The United States has called the charges against Ms. Saberi baseless and has demanded her release, and the conviction and prison sentence could put strains on efforts to improve ties.
President Barack Obama has said it wants to engage Iran in talks on its nuclear program and other issues — a departure from the tough talk of the Bush administration.
Iran has been mostly lukewarm to the overtures, but Iran's hard-line president gave the clearest signal yet on Wednesday that the Islamic Republic was also willing to start a new relationship with Washington.
In a speech, President Mahmoud Ahmadinejad said Iran was preparing new proposals aimed at breaking an impasse with the West over its nuclear program.
But it was uncertain how Washington would react to Ms. Saberi's conviction. On Thursday, the State Department said Ms. Saberi's jailing was not helpful and that Iran would gain U.S. good will if it “responded in a positive way” to the case.
Some conservative Iranian lawmakers played down Ms. Saberi's conviction, saying the verdict would not affect any ongoing efforts to build trust between Washington and Iran.
“Although there is a wall of mistrust between Iran and the United States, the judicial verdict won't affect possible future talks between the two countries. The verdict is based on evidence,” said lawmaker Hosseini Sobhaninia.
The United States severed diplomatic relations with Iran after its 1979 Islamic revolution and takeover of the U.S. Embassy in Tehran. Relations deteriorated further under the former president George W. Bush, who labelled Iran as part of the so-called “Axis of Evil” along with Saddam Hussein's Iraq and North Korea.
Iran's judiciary is dominated by hard-liners, which some analysts say are trying to derail efforts to improve U.S.-Iran relations.
Ms. Saberi's conviction comes about two months ahead of key presidential elections in June. Mr. Ahmadinejad is seeking re-election, but the hard-liner's popularity has waned as Iran's economy struggles with high-inflation and unemployment. The June 12 vote is pitting the hard-liners against reformists — led by a former prime minister Mir Hossein Mousavi — who support better relations with the U.S.
Human rights groups have repeatedly criticized Iran for arresting journalists and suppressing freedom of speech. The government has arrested several Iranian-Americans in the past few years, citing alleged attempts to overthrow its Islamic government through what it calls a “soft revolution.” But they were never put on trial and were eventually released from prison.
Journalist watchdog groups criticized the conviction. The New York-based Committee to Protect Journalists said in a statement on Saturday that her trial “lacked transparency.”
“We call on the Iranian authorities to release her on bail pending her appeal,” Mohamed Abdel Dayem, the group's Middle East and North Africa program co-ordinator, said in the statement.
NPR released a statement saying it was “deeply distressed by this harsh and unwarranted sentence.”
Iran has released few details about the charges against Ms. Saberi. Iranian officials initially said she had been arrested for working in the Islamic Republic without press credentials and she had told her father in a phone conversation that she was arrested after buying a bottle of wine.
An Iranian investigative judge involved in the case charged that Ms. Saberi was passing classified information to U.S. intelligence services.
Her parents, who travelled to Iran from their home in Fargo in a bid to help win their daughter's release, could not immediately be reached for comment on Saturday.
Ms. Saberi's father has said his daughter, who was Miss North Dakota in 1997, had been working on a book about the culture and people of Iran, and hoped to finish it and return to the United States this year.
“I'll bet my bottom dollar she has not been spying,” said Marilyn McGinley, president of the Miss North Dakota pageant, who said she has kept in touch with the journalist through telephone calls and e-mails.
“She is not a spy. She loved the people over there and her intention of going over there was to learn about her culture,” she said.
Ottawa Mens Centre.com, from Home of the Corrupt Ontario Superior Court Judge Allan Sheffield, Canada) wrote: Ms. Saberi is simply another hostage - its an "international problem" that will be addressed just as soon as the United States and Iran sit down together behind closed doors to discuss their mutual interests which both need urgently and desperately. Any delay in that meeting causes them both expensive penalties that neither wishes to incur but will occur if the issue of mutual face saving is not addressed.