Iranians began voting for a new president on Friday, with pragmatist cleric Akbar Hashemi Rafsanjani the front-runner in an unusually tight election. Polling stations opened at 9 a.m. (0430 GMT) to serve 47 million eligible voters across the country. Voters queued outside some polling booths in southern Tehran, according to Reuters. Supreme Leader Ayatollah Ali Khamenei, among the first to vote, told Iranians they would be endorsing not just their chosen candidate, but their country's Islamic system. "Whoever you vote for among those seven candidates, it's a vote for him, the Islamic republic and the constitution," he said after using a special ballot box at his official residence. Rafsanjani has topped most opinion polls ahead of what is expected to be Iran's closest election since the 1979 Islamic revolution. The moderate cleric, seeking to regain the office he held from 1989 to 1997, needs 50 percent support to avoid an unprecedented run-off between the two top vote-getters. His closest challengers are former education minister Mostafa Moin, 54, and conservative ex-police chief Mohammad Baqer Qalibaf, 43, although conservative former Tehran mayor Mahmoud Ahmadinejad is said to have gained ground.