TEHRAN (AFP) - Iran's reformist ex-president Mohammad Khatami on Sunday announced he would stand in June presidential elections in a challenge that could see the ouster of Mahmoud Ahmadinejad's government. "I strongly announce my candidacy in the elections," Khatami told a news conference after he held talks with an association of moderate clerics. "I never had doubt. Is it possible to remain indifferent toward the revolution's fate and shy away from running in the elections?" he asked. "I consider this as a right to run ... This candidacy doesn't deprive others and the path is open. What should be stressed is that the elections must be held freely." Khatami, 65, was president of Iran between 1997 to 2005. He was succeeded by President Ahmadinejad, who is set to stand again and has reportedly received the blessing of Iran's supreme leader Ayatollah Ali Khamenei. Khatami said it was important "to think about the fate of the nation and its long-time desire to be proud, free and to progress and reach justice." "I hope I can take steps to remove the people's problems and also enhance their position in the world." In his previous presidential term, Khatami inspired the Iranian youth with promises of social and political reforms, while Iran's relations with the West were less confrontational than they are now under Ahmadinejad. If he emerges victorious, expectations are that these ties, now frosty over Tehran's controversial nuclear programme, could begin to thaw. Western nations accuse Tehran of seeking to make atomic weapons under the guise of a civilian nuclear programme. Iran says its atomic ambitions are entirely peaceful. A close aide of Khatami warned that results of elections in Iran are always of "serious concern", referring to claims in the past of vote rigging. "But if the voter participation is high, we can easily win the election," said Mohammad Ali Abtahi. Several critics say Khatami was not firm enough against the establishments in the Islamic republic, leaving his mostly youthful supporters disillusioned and disappointed. Leading nationalists and liberal writers were assassinated in late 1998 in a series of brutal killings blamed on "rogue" intelligence service agents. Perhaps anticipating he would again challenge for the presidency, in the past two years the cleric has made a number of bold statements targeting not only Ahmadinejad but also the 12-member Guardians Council, one of the pillars of Iran's Islamic system. Ahmadinejad came under fire for his expansionary economic policies and confrontational international rhetoric while the Guardians Council was criticised for having the power to veto parliamentary bills and stop candidates from standing in elections. "What right do we have to decide in the place of the electorate and prevent the candidature of people who have the confidence of the people only because six or 12 people do not approve them?" he asked. Hardliners were enraged last year when he made a speech at a university, which was interpreted as accusing Iran's clerical leaders of supporting insurgents in the Middle East.