Voting got under way Friday in Iran's presidential election that is widely seen as a choice between incumbent Hassan Rouhani, a moderate reformist, and his hard-line conservative rival Seyed Ebrahim Raisi, a former attorney general.
More than 56 million Iranians are eligible to cast ballots at around 63,500 polling stations set up across country, which opened at 8 a.m. and will close at 6 p.m.
Presidential elections are held every four years in Iran and this one will be the 12th since the Islamic Revolution in 1979.
The latest voter survey predicted voter turnout at over 70 percent and showed Rouhani, a former cleric, lawyer, academic, diplomat and nuclear negotiator, leading Raisi by 15 percentage points.
The two are competing neck-and-neck in major cities like Tehran, Mashahd, Ahwaz and Shiraz.
"The competition between Rouhani and Raisi is very close and complicated and there is even the possibility of a runoff," a high-ranking official told Kyodo News on condition of anonymity.
In April, Iran's Guardian Council announced the name of six qualified candidates, out of 1,600 who registered for candidacy.
Subsequently, Tehran Mayor, Mohammad Bagher Ghalibaf, who was one of the major conservative candidates, stepped aside in favor of Raisi, while on the moderate side, First Vice President Eshaq Jahangiri quit the race in favor of Rouhani.
Also running in the election are Seyed Mostafa Mirsalim and Seyed Mostafa Hashemi Taba, both independent candidates who are not seen as serious rivals to Rouhani and Raisi.
Former Vice President Mohammad Ali Abtahi, now a political analyst, told Kyodo News that the chance of Rouhani winning is higher because most Iranians are happy with his latest reforms and he also enjoys the support of younger voters.
"Raisi's presidency is fearful for most youth, artists, athletes and social activists, so they would prefer to keep President Rouhani for a second term," he added.
When Rouhani took office in 2013, Iran was under heavy U.S. and EU sanctions and the inflation rate was over 40 percent, while many Iranians lived under the shadow of a possible war with the United States and its allies.
Lifting nuclear-related sanctions and interaction with the world community was one of Rouhani's major promises besides resolving the country's economic problems.
After two years of intense negotiations with six major world powers -- France, Russia, China, Germany, Britain and United States -- Rouhani's government clinched a landmark deal in 2015 to curb Iran's nuclear activities in return for an end to crippling economic and banking sanctions.
Soheil, 26, a civil engineer who works and lives in Tehran, said he supports Rouhani as the president made peace with the world community, which led to threats fading away and which hopefully will continue.
Mahsa, 28, an elementary school teacher in Tehran, said she supports Rouhani in order to say "no!" to extremism.
But others are less impressed by Rouhani's track record.
Ahmad Tavakkoli, an economist and former head of the Iranian parliament's Economic Research Center, told Kyodo News that Rouhani did not perform well on the economy, failing to find practical solutions for unemployment and to tackle financial corruption, for example.
"I think the nuclear deal was not successful because unfortunately it has not been implemented completely," he said, criticizing the United States for not fulfilling its commitments and approving other kinds of sanctions in the meantime.
Tavakkoli suggested that Raisi could be better at unifying business groups and companies in the country to achieve an integrated economy.
During Rouhani's four years in power, the inflation rate fell from 40 percent to 8.6 percent, while crude oil exports were boosted considerably and Iran signed a number of post-sanction financial contracts with western companies, including leading aircraft and auto manufacturers.
Behzad, a 33-year-old clothing shop operator in Tehran, said he will vote for Raisi because he thinks that Rouhani never trusted his own people's ability to rebuild the economy and instead looked outside of Iran for economic solutions.
"Over the last four years Rouhani was hoping to get help from Western countries. He didn't rely on domestic capacities," he said.
Mahmoud, a 56-year-old citizen in Mashahad, the second biggest city in Iran, described the nuclear deal as "a mess" and said Rouhani should be tried in court for signing it.
"The nuclear deal was supposed to be a win-win deal but we have lost. Based on this deal we have reduced our nuclear capability in return for nothing," Mahmoud said. "We haven't gained anything."