TEHERAN, Iran – Iran's nuclear chief on Tuesday said the head of the UN watchdog agency made a dangerous mistake by criticizing Teheran for not fully cooperating.Yukiya Amano, the head of the International Atomic Energy Agency, said Monday that he cannot confirm that all of Iran's nuclear activities are peaceful, as Teheran claims, because the country has offered only selective cooperation to the UN nuclear watchdog and has rejected several inspectors.RELATED:Yatom: Only attack will stop IranReport: Iranian uranium enrichment site revealed"If Mr. Amano has expressed the remarks knowingly, he has committed a big mistake and it is very dangerous," said Ali Akbar Salehi, the head of Iran's nuclear program. He said this would amount to outside pressure on Iran.In blunt remarks, Amano suggested that it is still not clear whether Iran is developing nuclear weapons because the country continues to stonewall an IAEA probe.Salehi reiterated Iran's right to choose inspectors. Iran has rejected two inspectors, accusing them of leaking information on the country's nuclear program. The IAEA, however, has insisted on reinstating them.Iran is under increasing pressure by the West, including four rounds of UN sanctions, over allegations it is using its nuclear program as a cover for weapons development. Also on Tuesday, Akbar Hashemi Rafsanjani, a former president and head of a powerful council within Iran, warned about the rising number of international sanctions against Iran."We have never had so many resolutions against our governments by the international community including the UN Security Council and the IAEA," he said.The UN Security Council imposed a fourth set of sanctions on Iran in June after Teheran refused to halt is nuclear enrichment activities. Uranium enriched to more than 90 percent can be used for weapon. Iran says it currently enriches uranium up to 20 percent for medical radio isotopes and up to 3.5 percent to fuel a nuclear power plant. It says its program is only for peaceful purposes.