Iran on Monday dismissed US concerns about how much fissile material the country has produced, saying it does not plan to develop a nuclear bomb and that any effort to convert the material into weapons-grade uranium would be difficult under the eyes of international inspectors. The comments came a day after the chairman of the US Joint Chiefs of Staff, Adm. Mike Mullen, said Iran has sufficient fissile material for a nuclear weapon and warned of a dire outcome if Teheran moves forward with building a bomb. The International Atomic Energy Agency said Iran has processed 1,010 kilograms of low-enriched uranium. But the report left unclear whether Iran is now capable, even if it wanted, of further enriching that material to the much higher degree needed to build a warhead. Iranian Foreign Ministry spokesman Hasan Qashqavi told reporters in Teheran, "We have said many times that a nuclear weapon has no place in Iran's defense doctrine." Qashqavi did not comment specifically on the amount of fissile material Iran has produced. But he implied that even if Iran wanted to produce weapons-grade uranium, it would be difficult since the country's enrichment facility is being monitored by the IAEA. "How is it possible for uranium enriched 3 to 4 percent to be enriched up to 90 percent while under IAEA monitoring?" he said. Iran says its nuclear program aims only to generate electricity and has been producing uranium that is less than 5 percent enriched in line with fuel needs of modern reactors. Nuclear weapons use uranium that is enriched to about 90 percent. The US and many of its allies suspect Iran's real aim is to develop a program that would allow it to produce nuclear weapons and fear it will take the next step to further process its enriched uranium. International inspectors have not said Iran has taken that step. Uranium is enriched by spinning a uranium gas at supersonic speeds in a series of thousands of centrifuges, and the technology can be used to produce low-enriched uranium for fuel or high-enriched for a warhead. But the latter requires more complicated techniques, and experts say it is unclear whether Iran has mastered the process. US Defense Secretary Robert Gates, also appearing on a Sunday talk show, did not go as far as Mullen, saying the Iranians were not close to a weapon at this point, leaving time for diplomatic efforts. Gates appeared on NBC's "Meet the Press" Sunday, while Mullen was interviewed on "Fox News Sunday." US President Barack Obama has offered increased diplomatic engagement with Iran in a bid to prove Teheran has more to lose by ignoring the wishes of countries concerned about its uranium enrichment than it has to gain through its nuclear efforts. The UN has passed three sets of sanctions against Iran for its failure to suspend its uranium enrichment program.