An Iranian revolutionary court has sentenced US-Iranian journalist Roxana Saberi to eight years in jail on charges of spying for the US, her lawyer said yesterday.

The verdict - the harshest sentence ever meted out to a dual national on security charges in Iran - was greeted with shock by her father, who said Saberi had been "tricked" into confessing.

Saberi, 31, has been detained in the notorious Evin prison in Tehran since January and went on trial behind closed doors last Monday accused of spying for the US.

"Ms Saberi has been sentenced to eight years in jail and I am going to appeal," her lawyer Abdolsamad Khoramshahi told AFP. Under Iranian law, the verdict can be appealed within 20 days.

The case against Saberi, who has both US and Iranian nationality, has raised deep concerns in Washington and among rights' groups.

She was initially reported to have been detained for buying alcohol, an illegal act in the Islamic republic.

The ISNA news agency, quoting an unnamed judiciary source, confirmed that a revolutionary court had sentenced Saberi for espionage - a charge that could have risked the death sentence. No date was given for the verdict.

"Roxana said in court that her earlier confessions were not true and she told me she had been tricked into believing that she would be released if she co- operated," her father Reza Saberi told AFP.

"Her denial is documented in her case but apparently they did not pay attention to it," he added, without saying when he had spoken to his daughter.

"We are very shocked and we were not expecting it. We were hoping for six months and then clemency."

The court ruling comes despite calls by US Secretary of State Hillary Clinton for Saberi's release and President Barack Obama's diplomatic overtures to Iran after three decades of ruptured ties.

Several US-Iranians, including academics, have been detained in recent years on security charges, but released after several months behind bars.