a field of six candidates." border="0" height="360" id="articleGalleryPhoto001" width="640"/>Iranian youth ride their bicycles past campaign posters in downtown Tehran on Thursday, June 13, a day ahead of the country's presidential election. More than 50 million Iranian voters are eligible to go to the polls Friday to select a new president from
a field of six candidates.
Supporters of top nuclear negotiator and conservative presidential candidate Saeed Jalili wave national flags during his campaign rally at Heydarnia stadium in Tehran on Wednesday, June 12.
A supporter of Hassan Rouhani, moderate presidential candidate and former top nuclear negotiator, works on her laptop in one of his campaign offices in Tehran on Tuesday, June 11.
Iranian supporters of former vice president and reformist presidential candidate Mohammad Reza Aref shout slogans during his campaign rally in Tehran on Monday, June 10. Later on Monday he announced his decision to drop out of the race. Hours earlier, another candidate, Gholam-Ali Haddad-Adel, also said he was out.
under house arrest since February 2011, during a campaign rally for Aref in Tehran on June 10." border="0" height="360" id="articleGalleryPhoto005" width="640"/>A man holds a portrait of opposition leader Mir Hossein Mousavi, who has been
under house arrest since February 2011, during a campaign rally for Aref in Tehran on June 10.
A supporter of Iranian presidential candidate Mohsen Rezaei, Iran's top commander during the war with Iraq, holds a blue flag bearing his portrait during a rally in Tehran on June 10.
An Aref supporter checks her mobile phone surrounded by campaign posters after the June 10 rally in Tehran.
Pilgrims and clergymen walk across the courtyard of the Masoumeh holy shrine in the religious Shiite Muslim city of Qom on Sunday, June 9. Iran's powerful bazaar merchants and Shiite clergy spearheaded the 1979 Islamic revolution, but their role in the country's political scene has waned over the years, analysts say.
An Iranian clergyman walks past campaign posters on June 9 in Qom, south of the capital city of Tehran.
Iranians read the headlines on the front pages of newspapers unveiling the approved presidential candidates on May 22 in Tehran.
- Ayatollah Khamenei: ''go to ballot boxes as soon as possible''
- The last election resulted in raucous street protests known as the "green movement"
- Voting is not mandatory, but it makes a difference in promotions and collection of welfare
- The supreme leader must approve candidates seeking office
(CNN) -- Television cameras zoomed in on his hand Friday as Iran's supreme leader filled out the very first ballot in the national election to replace outgoing President Mahmoud Ahmadinejad.
Ayatollah Ali Khamenei slipped the folded paper into the ballot box and turned to the cameras. He called on the 50 million Iranians eligible to vote to take their pick of one of six candidates in the "epic" election.
"My expectation of our endeared people is for everyone to take part, and I would recommend that they go to ballot boxes as soon as possible and not to delay," he said.
After the "Green Movement" uprising that flooded Tehran's streets after Ahmadinejad's reelection in 2009, many voters, who back then asked "Where's my vote?" may sit this one out in protest.
Saeed Jalili is Iran's chief nuclear negotiator and represents Iran in talks with the European Union.
Mohsen Rezaei is currently a member of the Expediency Council and was Iran's top commander during the war with Iraq.
Hassan Rouhani is head of the Center for Strategic Studies and Iran's chief nuclear negotiator under former President Mohammad Khatami.
Mohammad Ghalibaf is a member of the Revolutionary Guard's Corp and currently the mayor of Tehran.
Mohammad Gharazi was a minister during Akbar Hashemi Rafsanjani's presidency.
Ali Akbar Velayati was twice foreign minister during the Rafsanjani presidency and is currently the Supreme Leader's top adviser.
Who's running for Iran's presidency?
Who's running for Iran's presidency?
Who's running for Iran's presidency?
Who's running for Iran's presidency?
Who's running for Iran's presidency?
Who's running for Iran's presidency?
Who's running for Iran's presidency?
Are sanctions against Iran working?
Environment in Tehran ahead of elections
Iran elections: Why 2013 isn't like 2009
Voting is not mandatory in Iran, but participating in elections opens up possibilities for promotion in the workplace and gives one preference when it comes to collecting social welfare benefits.
All candidates are pre-approved to run for the nation's highest elected office by Iran's Guardian Council, a nonelected body made up of six clerics and six lawyers operating under the oversight of the Supreme Leader.
It allows Khamenei to limit the election process. Out of 680 candidates, eight were approved. Two have dropped out of the race.
But this does not narrow down the race to only those close to him. He does allow reformists and centrists to run.
The six remaining candidates are: Mohammad Bagher Ghalibaf, Ali-Akbar Velayati, Saeed Jalili, Mohsen Rezaei, Hassan Rouhani, and Mohammad Gharazi.
Velayati, Ghalibaf and Jalili, who is Iran's chief nuclear negotiator, are considered close to the Khamenei and would be unlikely to challenge his authority.
Rouhani is a centrist.
In a blow to Ahmadinejad, his aide and protege Esfandiar Rahim Mashaei, a reformist, was among those excluded by the Guardian Council.
Though supported by the supreme leader in the 2009 election, Ahmadinejad has been considered too liberal by conservative, religious politicians and has often been at odds with Khamenei.
Some of Ahmadinejad's associates have faced heavy repressions, and hardliners attempted to
link the president to the largest embezzlement case in the country's history.
CNN's Laura Smith-Spark contributed to this report
