Mahmoud Ahmadinejad (born October 28, 1956) is an Iranian politician who served as the sixth President of Iran from 2005 to 2013. Before his presidency, he served as Mayor of Tehran from 2003 to 2005. During his two terms in office, Ahmadinejad became one of Iran's most internationally controversial figures, known for his hardline stance on Iran's nuclear program, his confrontational relationship with Western governments, and his inflammatory rhetoric, particularly regarding Israel and the Holocaust. His presidency coincided with a significant tightening of international sanctions on Iran. His disputed re-election in 2009 triggered massive protests known as the Green Movement, one of the largest political upheavals in post-revolutionary Iran. After leaving office, he fell out of favor with Supreme Leader Ali Khamenei. His bids to run in the 2017 and 2021 presidential elections were both blocked by Iran's Guardian Council.