In 2009 Ahmadinejad's victory was hotly disputed and marred by large protests that formed the "greatest domestic challenge" to the leadership of the Islamic Republic "in 30 years", as well as clashes with parliament. Despite high turnout and large enthusiastic crowds for reformist opponent Mir-Hossein Mousavi, Ahmadinejad was officially declared to have won by a 2–1 margin against three opponents. Allegations of voting irregularities and protest by Mousavi his supporters were immediate and continued off and on into 2011. Some 36–72 were killed and 4000 arrested. Supreme Leader Ali Khamenei declared Ahmadinejad's victory a "divine assessment" and called for unity. He and others Islamic officials blamed foreign powers for fomenting the protest.