Es'haq al-e-Habib, the deputy Iranian ambassador to the United Nations, said Washington has no right to be critical of what he said was a peaceful nuclear energy program.
Al-e-Habib said it was "ridiculous" that the only country to use nuclear weapons -- the United States -- is criticizing programs elsewhere in the world, Iran's state-funded broadcaster Press TV reports.
Iranian envoy to the IAEA Ali Asghar Soltanieh had said Iran was entitled to a peaceful nuclear program under international law, adding there were no plans to abandon the "inalienable" right to uranium enrichment.
The International Atomic Energy Agency said it was frustrated with Tehran's reluctance to grant access to some nuclear installations. The IAEA said there may be some military dimensions to certain aspects of Iran's nuclear program.
Iran last year started operations at the Bushehr plant with the help of Moscow. Russia, under an agreement with Iran, operates and supplies fuel for the plant.
Iranian Supreme Leader Ali Khamenei said last week that Tehran considers nuclear, chemical and similar weapons "a great and unforgivable sin," however.