"Esfandiari has been formally charged with endangering national security through propaganda against the system and espionage for foreigners," spokesman Ali Reza Jamshidi told reporters. "She has been informed of the charges against her."

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 also had been lodged against Kian Tajbakhsh, an urban planning consultant who also has 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.

Azima, who works for the U.S.-funded Radio Farda, was detained but released and barred from leaving the country. 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.

Laura Silber, a spokeswoman for Soros' Open Society Institute in New York said the organization was "dismayed at the charges" against Tajbakhsh, an "internationally respected scholar."

"The charges are completely without merit," Silber told The Associated Press by telephone. "We are very concerned for Dr. Tajkbakhsh's safety and urge the Iranian authorities to release him immediately."

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 revolts 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.

However, Jamshidi's statement that specific allegations had been read to Esfandiari and the others indicates the cases have been raised to a new level under the Iranian legal system.

The Associated Press telephoned a spokeswoman for the Soros Foundation in New York for comment, but she could not be reached due to the early hour in the United States.

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 is 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.