A supporter of Mirhossein Mousavi, presidential candidate and former Iranian Prime Minister, has a green ribbon, the symbolic colour of Mousavi's campaign, tied to his hand in Tehran May 26, 2009. Iranians vote on June 12 in an election that pits hardline President Mahmoud Ahmadinejad against two moderate challengers and one fellow-conservative. Mousavi, 67, is viewed by many moderates and even some conservatives as Ahmadinejad's strongest challenger for the presidency. REUTERS/Raheb Homavandi (IRAN)