Exclusive: Sources say senior Iranian diplomat detained in March By Louis Charbonneau UNITED NATIONS (Reuters) - A senior Iranian diplomat linked to Iran's reformists was detained in Tehran in March, possibly as part of a crackdown on dissidents ahead of the June presidential election, sources familiar with the case told Reuters on Tuesday. Bagher Asadi, who has previously been a senior diplomat at Iran's U.N. mission in New York and was most recently a director at the secretariat of the so-called D8 group of developing nations in Istanbul, was arrested in mid-March in the Iranian capital according to the sources, who requested anonymity. "We don't know why Ambassador Asadi was arrested," a source said, adding that it could be part of a pre-election crackdown. It was not clear where Asadi was being held, the sources said. Reuters was unable to independently verify any aspect of the matter - who arrested the 61-year-old diplomat, on what grounds or even if he had been detained. Iran's reformists have been sidelined since Mahmoud Ahmadinejad, the conservative former mayor of Tehran, won the presidential election in 2005, replacing reformist Mohammad Khatami. Iran's U.N. mission did not respond to a request for comment on the alleged arrest of Asadi, who in 2003 was appointed by former U.N. Secretary-General Kofi Annan to a panel of eminent persons on U.N. relations with civil society. Emails sent to Iran's Foreign Ministry and Interior Ministry generated automated responses that said their mailboxes were full. Last month Ahmed Shaheed, the U.N. special rapporteur on human rights in Iran, said Tehran's silencing of journalists and opposition leaders could jeopardize the legitimacy of the presidential election in June. Shaheed said dozens of Iranian journalists were behind bars, including 17 arrested during one week in January, and charged with communicating with foreign news outlets or rights groups. He added at least 10 lawyers were in custody for "spreading propaganda against the system" and other charges. Opposition leaders Mehdi Karoubi and Mirhossein Mousavi, both candidates in the 2009 presidential election, are under house arrest following mass protests over alleged fraud in the re-election of Ahmadinejad that year. Some analysts say Iran's Islamic clerical leadership sees the risk of more serious unrest in the June 14 election and is cracking down in advance to minimize the impact. In January 2004, Asadi wrote an opinion piece that ran in the New York Times in which he made clear his affinities with the reformist philosophy of Khatami. At that time, Khatami's push for reforms was buckling in the face of fierce opposition from conservatives. Asadi warned that conservative victories in 2003 local elections had emboldened "the conservative bloc and its authoritarian fringe," who were determined to retake Iran's parliament, the Majlis. He warned of the potential negative consequences of a conservative victory in the 2005 presidential election. Ahmadinejad won that election. Asadi also predicted that "the conservatives' blatant disdain for human rights and republican aspects of governance, among other things, would inevitably invite outside censure and further complicate an already tenuous relationship." Ahmadinejad has been vilified by many in the West for his anti-Israeli and anti-Western rhetoric and for repeatedly questioning the Holocaust. After he took office, Iran was hit with four rounds of U.N. Security Council sanctions over its nuclear program, along with more draconian U.S. and European sanctions. Ahmadinejad, who is completing his second and final term, has since fallen out of favor with Supreme Leader Ayatollah Ali Khamenei. According to diplomats and analysts, Iran's economy is in tatters due to a combination of sanctions and economic mismanagement. Iran says its nuclear program is peaceful but Western nations and their allies suspect it is aimed at developing the capability to produce atomic weapons. Additional reporting by Yeganeh Torbati in Dubai; Editing by Mohammad Zargham