WASHINGTON — Iran’s acknowledgment that it is holding a New York-based Iranian American urban planner who is believed to have first been arrested on May 11 is prompting a call to suspend the talks between America and Iran that began this week.

In an announcement one day after the first long-form talks between America and Iran since the 1979 hostage crisis, Iran’s judiciary ministry said it had formally charged Kian Tajbakhsh, a scholar with the New School in New York who is affiliated with George Soros’s Open Society Institute, on charges of espionage and plotting to destabilize the Islamic Republic.

The Iranians also announced similar charges against a journalist for the American-government-backed Radio Farda, Parnaz Azima, and a fellow at the Woodrow Wilson International Center for Scholars in Washington, Haleh Esfandiari.

Ms. Esfandiari, the wife of a scholar of the Iraqi Shia, Shaul Bakhash, has been one of Washington’s main proponents of engagement with Iran. The arrests this month of the American citizens suggest the regime is less interested in negotiations with the West than some of the critics of the Bush administration have suggested.

Yesterday the head of the Wilson Center, Lee Hamilton, who also was a co-chairman of the Iraq Study Group that recommended American engagement with Iran, said he was disheartened by the announcement of the charges against his scholar.

“The Wilson Center receives zero funding from the U.S. government’s fund to promote democracy in Iran,” Mr. Hamilton said. “Her detention is an affront to the rule of law and common decency. The Wilson Center’s message to the Iranian government is simple: Let Haleh go.”

The Open Society Institute yesterday also denied the charges from the Iranians. In a statement to the press, the institute pointed out that Mr. Tajbakhsh’s activities and the institute itself were not funded by the American government. “These charges are completely without merit. Mr. Tajbakhsh at one point consulted for Iran’s ministry of interior and social security ministry,” the statement said.

The arrests and pending trials for the three Americans come in the aftermath of disclosures by ABC News regarding a secret intelligence program aimed at destabilizing the regime without the use of lethal force. It also comes after American military commanders have charged that Iran is providing money and arms to both Sunni and Shia terrorists in Iraq.

Adding insult to injury, the Iranians have not even followed traditional consular agreements and allowed the Swiss embassy, which handles American business in Iran, access to the detained American citizens.

“Iran has so far failed to respond to the Swiss government’s request for consular access to the American citizens whom it has acknowledged detaining,” a State Department spokesman, David Foley, said yesterday. “We call on Iran to release these Americans immediately.”

Nonetheless, it appears that America is open to the prospect of future talks between America’s ambassador in Baghdad, Ryan Crocker, and his Iranian counterpart, according to one administration official.

Mr. Foley yesterday criticized the detentions and arrests of the three Iranian Americans and called for their immediate release, as well as the release of a former FBI officer, Robert Levinson, who has been missing in Iran since March 8.

“We will continue to work through the Swiss government, our protecting power for consular matters in Iran, in relation to the several cases of detained American citizens, and on the welfare and whereabouts of Bob Levinson,” Mr. Foley said. The vice president for foreign and defense policy studies at the American Enterprise Institute, Danielle Pletka, yesterday called on Secretary of State Rice to cancel the next talks being planned in Baghdad.

“This is outrageous. The whole thing is outrageous. First of all, the State Department seems to forget, these aren’t Iranian Americans, these are Americans. Number two, the fact that the Iranians preferred to make these charges against these hostages after having met in the first formal bilateral meetings between the U.S. and Iran, gives us a sense of how they see the hand they are playing. These talks should not be resumed until all the American hostages are freed,” she said.