TEHRAN (AFP) - The head of Iran's Atomic Energy Organisation Gholamreza Aghazadeh will not take part in the UN nuclear watchdog's annual assembly opening on Monday (today), the ISNA news agency reported on Sunday. The news agency quoted an unnamed official as saying that Aghazadeh would not be joining the September 29 to October 4 General Conference of the International Atomic Energy Agency in Vienna for "unknown reasons". But it said his deputy Muhammad Saeedi and the country's Ambassador to the IAEA, Ali Asghar Soltanieh, will represent Iran. Iran and Syria, both under fire for allegedly engaging in clandestine nuclear activity, have been seeking a seat on the board of the UN atomic watchdog, much to the consternation of Western states. The 35 members of the IAEA board are elected each year by the body's highest policy-making body, the General Conference, which comprises all 144 member states. The IAEA has been investigating Iran's nuclear drive for the past five years, but has so far been able to determine whether its programme is entirely peaceful as Tehran claims.