Iranian President Mahmoud Ahmadinejad on Monday labeled his critics at home "traitors" and accused them of spying and collaborating with Iran's enemies, state media reported. Ahmadinejad, who is facing growing domestic criticism over his hard-line policies that have led to UN Security Council sanctions, vowed to eventually publicly expose his critics, who he hinted as belonging to Iran's reformist camp. "They are traitors," the official IRNA news agency quoted Ahmadinejad as saying of his critics. "Based on the pledge (I) made with the people, we won't retreat and won't standby. ... We are not revealing them because of some sensitivities, but upon closure of the nuclear issue, we will reveal all these issues," IRNA quoted him as telling a group of students at Science and Industry University in Teheran. Ahmadinejad didn't specifically name any of his critics, but said he has resisted pressures not just from the West but from critics at home after his government took office in 2005. "They (his critics) sent people to the enemy to regularly give them information from within the ruling system every week. We even have a recorded speech of one of them who tells the enemy 'Why should you give up? ... Step up pressures to make them (Iran) retreat,"' the state television Web site quoted Ahmadinejad as saying. He did not elaborate on the alleged recorded speech or specifically say who the enemy was. Ahmadinejad's critics have stepped up vocal warnings in recent months that the president's hardline policies and defiance against international demands to roll back Iran's nuclear program were turning more countries against Teheran. Iran's former chief nuclear negotiator, Hasan Rowhani, who is an ally of Ahmadinejad's top rival, former President Ayatollah Akbar Hashemi Rasfanjani, delivered an unusually sharp rebuke last month to Ahmadinejad, saying he was making more enemies for Iran. In his speech Monday, Ahmadinejad said his critics were pressuring a judge who was investigating espionage charges against an official, but the president stressed he would not let that person to escape justice. "After we arrested one person because of espionage, they have put the judge under strong pressure to acquit the spy. But I announce here that the Iranian nation won't allow these persons and groups to save criminals from the clutches of justice," the television Web site quoted Ahmadinejad as saying. Ahmadinejad did not name the official facing espionage charges. But earlier this year, Hossein Mousavian, another Rasfanjani ally who was a former top nuclear negotiator under former reformist President Mohammad Khatami, was briefly detained. Authorities have not said what charges he faces, but the semiofficial Fars news agency has reported that the charges were likely related to espionage. When he came to power in 2005, Ahmadinejad removed the previous nuclear negotiating team under Khatami, including Rowhani and Mousavian, which he had accused of making too many concessions. He installed his own team and has since taken a tough line, refusing to bend to UN demands that Iran halt uranium enrichment. Last month, Ali Larijani, who was Iran's top nuclear negotiator, resigned and was replaced by a little known diplomat in a move seen as a victory for Ahmadinejad that could push the country into an even more defiant position in its standoff with the West. Suspicions over the purpose of Iran's nuclear program have led the UN Security Council to impose sanctions over Teheran's refusal to halt its enrichment program. The enrichment process can be used for generating energy or producing the fissile core of nuclear warheads. The United States and some of its allies accuse Iran of secretly trying to develop nuclear weapons - a charge Iran denies, saying its program is for peaceful purposes including generating electricity.