Iranian authorities say American-Iranian journalist Roxana Saberi will stand trial next week on charges of spying.
Deputy Prosecutor Hassan Haddad announced the espionage case Wednesday, more than two months after Saberi was detained in Tehran's Evin prison.
An investigative judge, identified only by his last name, Heidarifard, involved in the case told Iranian state television that Saberi used journalism as a cover to pass classified information to U.S. intelligence services.
The charge is far more serious than officials initially indicated. She was earlier accused of working illegally in the country without valid press credentials.
The U.S.-born journalist has dual Iranian and American citizenship. The 31-year-old Saberi lived in Iran for six years and reported for several Western news agencies before being detained.
Iranian officials say Iran's Revolutionary Court, which handles security issues, is reviewing Saberi's case.
Saberi's lawyer, Abdolsamad Khorramshahi, told VOA's Persian News Network Wednesday he last saw his client three weeks ago and knew that she had been formally charged, but had not been allowed to read the dossier on her case.
U.S. Secretary of State Hillary Clinton said Wednesday she was very concerned by news of the espionage charge and called for Saberi's immediate release.
During a news conference in Washington Wednesday, Clinton said the State Department has asked Swiss diplomats to obtain the latest information on Saberi.
Switzerland acts an intermediary between Washington and Tehran, as the two countries do not have diplomatic relations.
The Committee to Protect Journalists issued a statement Wednesday expressing deep concern over the reports Saberi has been charged with espionage.
Saberi's parents are currently in Iran, and met with their daughter Monday. She was reported to be doing well.