Authorities announced new arrests in the cases of two Iranian-Americans held on charges of conspiring against the government, saying Wednesday that an unspecified number of Iranians had been detained.
State radio quoted Intelligence Minister Gholam Hossein Ejehei as saying that: "Internal elements related to these people have been arrested."
Ejehei did not say how many people were arrested or give details on their purported connections to Haleh Esfandiari and Kian Tajbakhsh.
"We are hopeful their names and reasons of detention will be announced," he said.
The Intelligence Ministry has alleged that Esfandiari and Tajbakhsh were seeking to set up networks of Iranians to foment a "velvet revolution" against Iran's Islamic government. Families and employers of the two have denied the charges.
Esfandiari, 67, the director of the Middle East program at the Washington-based Woodrow Wilson International Center for Scholars, has been held largely incommunicado since May.
Tajbakhsh, an urban planning consultant with the Soros Foundation's Open Society Institute, has been held since May.
Last week, Iranian state television aired footage of Esfandiari and Tajbakhsh in a program that it said detailed the allegations against them. The 50-minute program showed a montage of disparate quotes combined to form what could be interpreted as incriminating statements, which their supporters and the U.S. government called illegitimate and coerced.
The footage also prompted criticism from moderates in Iran.
Two other Iranian-Americans face similar charges: Parnaz Azima, a journalist who works for the U.S.-funded Radio Farda, and Ali Shakeri, a founding board member of the University of California, Irvine, Center for Citizen Peacebuilding. Shakeri is in prison, while Azima is free but barred from leaving Iran.
The detentions have become another point of contention in the stormy U.S.-Iranian relationship. The United States accuses Iran of arming Shiite militants in Iraq, fueling unrest in Lebanon and seeking to develop nuclear weapons. Tehran denies those claims, and blames the United States for Iraq's instability.
The U.S. has detained five Iranians who the United States has said are the operations chief and members of Iran's elite Quds Force, which is accused of arming and training Iraqi militants. Iran says they are diplomats who were legally in Iraq, and demanded their immediate release.