Gholamreza Aghazadeh, Iran's nuclear energy chief, also urged the International Atomic Energy Agency to widely publish the report it released to member nations last week on Iran's nuclear program.
Iran's nuclear program is at the heart of rising tensions between Washington and Tehran. The Iranian foreign ministry said Monday that the United States is applying pressure to Iran because it resents its independent foreign policy.
Foreign Ministry spokesman Hamid Reza Asefi said the pressure will backfire.
"America's entire propaganda against Tehran is because of Iran's independent foreign policy. This is what the U.S. administration dislikes," he said.
The Bush administration accuses Iran of wanting to build a nuclear bomb and wants the U.N. agency to declare Iran in breach of the treaty. Iran says its nuclear program is for peaceful purposes.
Aghazadeh said the IAEA report did not back up U.S. claims that Iran was violating international atomic protocols.
"There is no mention of the word 'violation,'" he told state-run television. "The report only mentions 'failure,' which is still a legal debate between us. And these are normal differences."
On Friday, a diplomat from an IAEA member state said the report indicated Iran had imported some nuclear material and processed it without declaring it to the Vienna, Austria-based agency.
Aghazadeh said the report notes that in 1991 Iran imported a small quantity of uranium hexofluoride, the chemical form of uranium used for the enrichment process.
IAEA regulations at the time did not require Tehran to inform the agency of the acquisition, he said.
Aghazadeh did not say why Iran imported the uranium but acknowledged that the report says Iran "should have informed" it of the acquisition.
Iran has since identified the materials to the IAEA, which now has them under "safeguard," he said.
The report will be discussed publicly when the agency's board meets June 16.
Three IAEA inspectors arrived in Iran on Saturday to assess the country's nuclear activities. The visit is widely seen as a chance for Iran to counter U.S. accusations of a nuclear weapons program and show it is eager to cooperate with the agency.
In February, Mohamed ElBaradei, head of the IAEA, visited the incomplete Natanz nuclear plant about 200 miles south of Tehran. Diplomats accompanying him said he was taken aback by the advanced stage of a project there using hundreds of centrifuges to enrich uranium.
Also Sunday, Supreme leader Ayatollah Ali Khamenei said Washington's outcry over Iran's nuclear capabilities is an attempt to block Iran's economic progress.
"By making accusation against Iran, the United States wants to play down the social progress the Iranian nation has achieved in the past 24 years," the official Islamic Republic News Agency quoted him as saying.
Secretary of State Colin Powell told CNN on Sunday that Washington was not seeking regime change in Iran but said many young Iranians were dissatisfied with Tehran's political leadership.
"What we have to do is keep showing to the Iranian people that there is a better world out there waiting for you, and you can become a more responsible member of the international community if you stop supporting terrorist activity and if you stop trying to develop weapons of mass destruction," Powell said.
He told Fox that the U.S. message to those restive people is to "put pressure on your political leaders and your religious leaders to allow more innovation within the Iranian society, within the Iranian economy, to start changing the policies of the past."
Washington accuses Iran of sponsoring terrorist groups and recently claimed Tehran was harboring members of Osama bin Laden's al Qaeda network.
Iran rejects the claims, but admits to holding unidentified al Qaeda members in custody and says it will deport them to their home countries once their identities are confirmed.
The Washington Post reported last month that the administration has cut off contacts with the Iranian government and appeared prepared to begin an aggressive policy of trying to destabilize it.
A White House spokesman said at the time that there was no change in U.S. policy, that Iran must stop supporting terrorists and end illicit weapons programs.