Iran on Sunday denied reports that nuclear activities had stalled at one of its uranium enrichment plants and reiterated it would press ahead with the program which the West fears could be used to make nuclear arms. "Activities in Natanz continue," Mohammad Ali Hosseini, spokesman of Iran's Foreign Ministry, said during a weekly media briefing, in response to a question whether nuclear enrichment at the plant had stopped. On Thursday, diplomats in Vienna - headquarters of the International Atomic Energy Agency which inspects Iran's declared nuclear sites - had said that despite tough talk from Teheran leaders, Iran's uranium enrichment program appears stalled, leaving intelligence services puzzled. Deputy chief of Iran's atomic energy organization, Mohammad Saeedi, promptly dismissed the suggestions by the diplomats accredited or otherwise linked to the Vienna-based IAEA that the current calm at the Natanz site could be a front. While the world's attention is focused on Natanz, Iranian scientists and military personnel could be working on a secret enrichment program at some unknown and possibly more advanced site, according to the diplomats, who had demanded anonymity in exchange for discussing restricted information. There have been no signs of any activity linked to plans to assemble 3,000 centrifuges at Natanz and move them into an underground facility as the start of an ambitious program foreseeing more than 50,000 centrifuges producing enriched material, the diplomats said. "Iran has a plan for production of nuclear fuel, so it should not cross anybody's mind Iran might stop its activities," Saeedi said. Earlier in January, two inspectors from the IAEA arrived here to inspect Iran's nuclear facilities in Natanz and Isfahan. Iran's parliament had urged the government in late December to re-examine its ties with the UN nuclear agency following a Security Council decision to impose limited sanctions against Teheran over its refusal to cease enrichment of uranium - a process that produces the material for either nuclear reactors or atomic bombs. Iran says that as a signatory to the Nuclear Nonproliferation Treaty it has the right to develop a peaceful uranium enrichment program to produce nuclear power. The United States and its European allies suspect Iran's civilian nuclear program is a cover for developing a nuclear bomb. Iran denies the charges and says its program is strictly for generating electricity. Criticism of President Mahmoud Ahmadinejad's hard-line nuclear diplomacy tactics has recently increased at home, in the wake of municipal elections last month in which candidates associated with the president sustained a humiliating defeat.