Tehran denies that "a cordial exchange" or "negotiation" took place at a conference between a US presidential envoy and an Iranian diplomat.
"As talks between Iran and the US have not been on the agenda, there has certainly been no negotiation with the American envoy," Iran's delegation to a conference on Afghanistan in The Hague said in a statement.
Iranian Deputy Foreign Minister Mohammad-Mehdi Akhoundzadeh explained on Wednesday that Iran "does not oppose such encounters, but the conference was about assisting Afghanistan and not about settling our differences. We are not in a game of hide-and-seek; we pursue an unambiguous and transparent policy."
Secretary of State Hillary Rodham Clinton on Tuesday, however, confirmed that Akhoundzadeh and the US envoy to Afghanistan, Richard Holbrooke, had a chat on the sidelines of the Tuesday conference -- which was aimed at restoring security in Iran's violence-stricken neighbor.
"In the course of the conference today our special representative for Afghanistan and Pakistan, Richard Holbrook had a brief and cordial exchange with the head of the Iranian delegation," Clinton told reporters.
"It was cordial, unplanned and they agreed to stay in touch," she added.
Washington has also reportedly handed a letter to the Iranian delegation, urging an intervention in the case of an American claimed to be missing in Iran and two Iranian-Americans currently under arrest in Iran.
"Separately at my direction, a letter was delivered to the Iranians focusing on three US citizens currently unable to return to the United States from Iran." Clinton said.
Details of the letter refer to US State Department claims that former FBI agent Robert Levinson went missing during a 2008 trip to Iran's Kish Island.
Tehran has rejected reports that it was holding the former US agent in detention. "We have no one with such a name in our custody," Judiciary spokesman Alireza Jamshidi said on February 17.
Iranian officials have repeatedly said that they have no information about Levinson's whereabouts or whether he disappeared in the country's territory.
Levinson's wife Christine and their son Daniel visited Tehran last December to hold talks with officials from the Iranian police force and Foreign Ministry -- who tried to help find the former agent. Their meetings, however, failed to shed any light on the Florida resident's whereabouts.
In reference to the two Iranian-Americans currently under arrest in Iran, Iranian-American journalist Roxana Saberi was arrested last month on charges of working "illegally" as a reporter after her press card was revoked in 2006.
During her six-year stay in Iran, the 31-year-old freelance journalist has reported for the BBC, NPR and Fox News.
In another case, Esha Momeni, a 28-year-old Iranian-American student from California's State University, was arrested on October 15. She was later charged with acting 'against national security' and 'propagating against the Islamic Republic'.
Momeni was later released from custody on a $200,000 bail but is not allowed to leave the country until she stands trial before a political tribunal.