Authorities arrested a number of Iranians allegedly connected to detained American scholars, the intelligence minister announced Wednesday, widening a sweep against what the government claims is a plot to overthrow the country's Islamic leadership.

Iran claims that four detained Iranian-Americans — who include scholars and a journalist — were trying to set up a network of Iranians with the long-term goal of sparking a pro-democracy "velvet revolution" in the country.

The families and employers of the four have denied the claims, and the detentions have become a new point of contention in stormy U.S.-Iranian relations, already tense over the violence in Iraq and over Iran's nuclear program.

Wednesday's announcement was the first time authorities have reported arrests of Iranians in connection to the alleged plot — suggesting they were now moving against local figures they view as involved in the purported network.

Intelligence Minister Gholam Hossein Ejehei did not say how many people were arrested, saying only they were believed connected to detained Americans Haleh Esfandiari and Kian Tajbakhsh.

"Internal elements related to these people have been arrested," state radio quoted Ejehei as saying. "We are hopeful their names and reasons of detention will be announced."

Iranian officials could not be reached for further explanation.

Esfandiari, 67, and Tajbakhsh, 45, have been detained since May, held in Tehran's Evin prison. They have been accused of endangering Iran's national security, but Iran has not said when and if they would be put on trial — and it was not clear if the new arrests meant trials were on the horizon.

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.

Esfandiari is the director of the Middle East program at the Washington-based Woodrow Wilson International Center for Scholars, where she ran a program of brining Iranians to the United States to deliver lectures on the situation in the country.

Tajbakhsh is an urban planning consultant with the Soros Foundation's Open Society Institute, a pro-democracy group.

Last week, Iranian state television aired footage of Esfandiari and Tajbakhsh in a program aimed at detailing the allegations against them. Their families dismissed the footage as propoganda and said the statements they made in it were coerced.

In the footage, the two are seen describing their work and their goals of promoting democracy and civil society — and their comments were combined in a way to seem to implicate them in a plot.

The U.S. State Department said it was "appalled" by the airing of the footage, which even raised some criticism from moderates in Iran.

Alongside the arrests of the Iranian-Americans, the government of hardline President Mahmoud Ahmadinejad has been cracking down on some Iranian non-governmental organizations and has increased warnings to the public of American plots against the country.

Tensions with the U.S. have been high this year, with Washington accusing Tehran 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.

Ambassadors from the two countries held a second round of face-to-face talks in Baghdad on Tuesday aimed at calming violence in Iraq. While the talks became heated with exchanged of accusations, the two sides agreed to set up a security committee to carry forward talks on restoring stability in the wartorn nation.

Iranian Foreign Minister Manouchehr Mottaki said Wednesday that his country was ready to consider higher level talks with the United States."The issue of negotiations between Iran and the U.S. about Iraq at the level of deputy foreign ministers is reviewable," he said, according to the state news agency.