TEHRAN - Three U.S. citizens detained in Iran and charged with espionage will stand trial, Foreign Minister Manouchehr Mottaki said on Monday, in a case that could further strain relations between Tehran and Washington.

The three were held after they strayed into Iran from northern Iraq at the end of July. U.S. Secretary of State Hillary Clinton has said Washington strongly believed there was no evidence to support any charges against them.

They have entered Iran with suspicious aims. The judiciary will try them, Mottaki told a news conference, adding that relevant sentences would be issued. He did not elaborate.

Last month, Iran's judiciary announced espionage charges against the three -- Shane Bauer, 27, Sarah Shourd, 31, and Josh Fattal, 27. Their families said they were hiking and had strayed across the border accidentally.

The case comes at a time of high tensions between Iran and the West over Tehran's nuclear plans and after Iranian officials accused foreign nations of fuelling unrest after a disputed presidential election in June.

The United States cut diplomatic ties with Tehran after Iran's 1979 Islamic revolution. The two countries are now embroiled in a row over Iran's nuclear programme, which the West suspects is aimed at making bombs. Tehran denies this.

Under Iran's Islamic law, sharia, espionage can be punishable by death.

President Mahmoud Ahmadinejad suggested in an interview with the American television network NBC in September that the Americans' release might be linked to the release of Iranian diplomats he said were being held by U.S. troops in Iraq.

Iran's Foreign Ministry earlier this month said it believed 11 Iranians were being detained in the United States, including a missing nuclear scientist and a former deputy defence minister who disappeared in 2007.

Ahmadinejad's re-election sparked Iran's worst unrest since the revolution. Authorities deny vote-rigging and portrayed huge opposition protests that erupted after the poll as a foreign-backed bid to undermine the Islamic state.
In November, the families of the three Americans appealed again for their release, saying they feared for their mental well-being after more than three months in captivity.

Clotilde Reiss, a French teaching assistant, was arrested in Iran on spying charges on July 1 in connection with the post-vote unrest. She was released on bail in August but not allowed to leave the country.

(Reporting by Hashem Kalantari; writing by Fredrik Dahl; editing by Diana Abdallah)

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