Saberi was jailed on April 18 on charges of spying for the United States, Iran's arch foe. The case could complicate Washington's efforts toward reconciliation with the Islamic Republic after three decades of mutual mistrust.

Her father said the 32-year-old was "very weak" after refusing food for two weeks in Tehran's Evin prison in protest at the verdict. Reza Saberi said his daughter fainted a few days ago and had been given intravenous fluid.

Judiciary spokesman Alireza Jamshidi said he had no information about this. He denied that Saberi was on hunger strike and said she was in good health.

The U.S. administration of President Barak Obama, who has offered a new beginning of engagement with Iran if it "unclenches its fist," says the espionage charges against Saberi are baseless and has demanded her immediate release.