Iran's presidential run-off will see a loyalist of the country's supreme leader face off against a moderate lawmaker on July 5 after no candidate secured enough votes in the first round of voting on Saturday.
Friday's vote to replace Ebrahim Raisi after his death in a helicopter crash came down to a tight race between a low-profile lawmaker Massoud Pezeshkian, the sole moderate in a field of four candidates, and former Revolutionary Guards member Saeed Jalili.
The Interior Ministry said neither secured the 50% plus one vote of over 25 million ballots cast required to win outright, with Pezeshkian leading with over 10 million votes ahead of Jalili with over 9.4 million votes.
Power in Iran ultimately lies with Supreme Leader Ayatollah Ali Khamenei, so the result will not herald any major policy shift on Iran's nuclear program or its support for armed groups across the Middle East.
However, the president runs the government day-to-day and can influence the tone of Iran's policy.
The clerical establishment hoped for a high turnout as it faces a legitimacy crisis fueled by public discontent over economic hardship and curbs on political and social freedom.
However, turnout in Friday's vote hit a historic low of about 40%, based on an Interior Ministry count released Saturday.
The election comes at a time of escalating regional tension due to the war between Israel and Iranian allies Hamas in Gaza and Hezbollah in Lebanon, as well as increased Western pressure on Iran over its fast-advancing nuclear program.
With Iran's supreme leader now 85, it is likely that the next president will be closely involved in the process of choosing a successor to Khamenei, who seeks a fiercely loyal president who can ensure a smooth eventual succession to his own position, insiders and analysts say.
Anti-Western views of Jalili, Iran's former uncompromising nuclear negotiator, offer a contrast to those of Pezeshkian. Analysts said Jalili's win would signal the possibility of an even more antagonistic turn in the Islamic Republic's foreign and domestic policy.
But a victory for mild-mannered lawmaker Pezeshkian might help ease tensions with the West, improve chances of economic reform, social liberalization and political pluralism.
Pezeshkian, faithful to Iran's theocratic rule, is backed by the reformist faction that has largely been sidelined in Iran in recent years.
"We will respect the hijab law, but there should never be any intrusive or inhumane behavior toward women," Pezeshkian said after casting his vote.
He was referring to the death of Mahsa Amini in 2022 while in morality police custody for allegedly violating the mandatory Islamic dress code.
The unrest sparked by Amini's death spiraled into the biggest show of opposition to Iran's clerical rulers in years.