"Esfandiari has been formally charged with endangering national security through propaganda against the system and espionage for foreigners," Judiciary spokesman Ali Reza Jamshidi told reporters. "She has been informed of the charges against her. The complainant is the Intelligence Ministry."
Jamshidi did not say when the specific allegations had been read to Esfandiari, director of the Middle East Program at the Washington-based Woodrow Wilson Center for Scholars. She has been held at Tehran's notorious Evin Prison since early May.
Jamshidi said the same charges had also been lodged against Kian Tajbakhsh, an urban planning consultant who has also worked for the World Bank, and journalist Parnaz Azima. No trial date has been announced and Jamshidi said the investigation against all three is continuing.
It was the first time the government has confirmed the arrest of Tajbakhsh, who was believed to have been taken into custody around May 11, according to George Soros' Open Society Institute. Azima, who works for the U.S.-funded Radio Farda, was detained but released and barred from leaving the country.
The Intelligence Ministry has accused Esfandiari and her organization of trying to set up networks of Iranians with the ultimate goal of creating a "soft revolution" in Iran, along the lines of the revolutions that ended Communist rule in Eastern Europe after the fall of the Soviet Union.
The Ministry has alleged that the Open Society Institute, which seeks to promote democracy, was part of the conspiracy.
Esfandiari's family, the Wilson Center and the Open Society Institute deny the allegations.
Under Iranian law, the distinction between someone being accused and charged is less clear than in the United States and many Western countries, especially in matters of national security. Security courts have wide latitude, with the option of dropping the proceedings at any time or even holding trials in secret.
The Associated Press telephoned a spokeswoman for the Soros Foundation in New York for comment but she could not be reached.
The 67-year-old Esfandiari has for years brought prominent Iranians to Washington to talk about the political situation in Iran, some of whom have been subsequently detained and questioned back home. Her defenders say some of those she brought to the U.S. were supporters of the Iranian government who sought to explain Tehran's stance to Americans.
Esfandiari had been trapped in Iran since December, when three masked men with knives stole her luggage and passport as she headed to the airport to leave the country, the Wilson Center said. In the weeks before her arrest, she was called in for questioning daily on her activities, it said.
Iran has stepped up accusations that the United States trying to use internal critics to destabilize the government. Tensions have mounted between the two countries over Iran's nuclear program and U.S. allegations that the Iranians have been supporting armed groups in Iraq.
President Mahmoud Ahmadinejad's hardline government has also increased restrictions on local non-governmental organizations, particularly women's rights groups and other critics.