"Yes, Saberi has been charged with espionage," he said.
The charges against her come two days after her parents visited their daughter in prison. The couple from North Dakota met Saberi for half an hour at Evin prison - the first time they had spoken to her since she called them on Feb. 10 to say she had been arrested.
The 31-year-old U.S.-born journalist has reported for the BBC, NPR and other media. She was arrested in late January. Iranian officials said at the time that she was working in the Islamic Republic with expired press credentials.
Her parents, Reza and Akiko, arrived in Iran on Sunday as part of their efforts to seek her release.
Saberi is being held in Evin prison, north of the capital Tehran. Earlier, the Foreign Ministry said she had engaged in "illegal" activities because she continued working in Iran after the government revoked her press credentials in 2006.