Iran's supreme leader, Ayatollah Ali Khamenei, pointed to the International Atomic Energy Agency's latest report, which concludes Iran was trying to build a nuclear bomb.
Khamenei told Iranian diplomats in Tehran Sunday: "The IAEA reports indicate this international body is not independent. The IAEA should not bow to pressure from America and some other countries because such unilateral actions will harm the reputation of the IAEA and the United Nations," the Los Angeles Times reported.
The Feb. 18 IAEA report, the first since Japanese diplomat Yukiya Amano replaced Egyptian Mohamed ElBaradei in December as head of the Vienna-based agency, warned Iran was apparently taking steps toward development of an atomic weapon.
The United States and its allies believe Iran is trying to develop the capacity to build a nuclear bomb. Iran has denied the claims, saying its nuclear program is for civilian use.
Iran's foreign minister, Manouchehr Mottaki, told Arabic-language al-Alam television news channel documents the IAEA cited are forgeries. Mottaki called Amano "a non-starter and a novice" who "has a long way to go to find a precise knowledge of (Iran's nuclear) issue."
U.S. leaders are considering additional sanctions against Iran for its lack of candor about its nuclear program.
Western leaders, already anxious in the months since the revelation of a secret uranium-processing plant in Iran, expressed more concerns last week when the country said it would refine uranium to 20 percent. That level, which would violate U.N. standards, is necessary before trying to further refine to a level needed for nuclear weapons.