The Iranian Government says there are no plans for a visit to Iran by a team from the United States Congress.
US aid workers helped in Bam's relief effort
The statement comes a day after two Republican members of Congress announced that they were sending aides to Iran in February.
This would be the first official US visit there since the two countries broke ties after the Islamic Revolution in Iran in 1979.
However, Tehran suggested no such trip might be on the agenda.
Reports of a forthcoming visit emerged in Washington, following a meeting on Wednesday between Iran's UN ambassador Mohammad Javad Zarif, Senator Arlen Specter and Representative Bob Ney.
Afterwards Mr Specter said Iran was "skittish" about formal government-to-government talks but would accept a staff delegation.
He said he hoped the visit would be followed by trips to Tehran by members of Congress and later by Bush administration policy-makers.
However on Saturday Iran's Irna news agency quoted Foreign Ministry Spokesman Hamid Reza Asefi as saying: "No planning has been made for the visit of American Congress and Senate representatives to Iran."
It was not clear if Mr Asefi was rejecting the planned visit by congressional aides, or just the prospect of a later visit by members of Congress.
The US State Department said it would have no objections to a congressional visit to Iran.
"It would be fine with us if they decided to go," spokesman Richard Boucher said on Friday.
Two years ago that President George Bush included Iran in his "axis of evil" along with Iraq and North Korea.
Washington suspects Tehran of seeking weapons of mass destruction and has put pressure on Tehran to open its nuclear facilities to international inspection.
But recently there have been signs of a thawing of relations.
The US provided relief assistance to the Iranian city of Bam, devastated by an earthquake in December, and offered to send a humanitarian delegation to Tehran.