Supporters of Iranian presidential candidate Mir Hossein Mousavi wave green flags -- his campaign colour -- as they attend a pro-reform rally at Haydarniya Stadium in Tehran on June 9, 2009. Mousavi, a former Iranian premier who has emerged as the main challenger to President Mahmoud Ahmadinejad in the June 12 election, sees himself as a "reformist" guided by the principles of the 1979 Revolution. AFP PHOTO/ATTA KENARE (Photo credit should read ATTA KENARE/AFP/Getty Images)