Reformist candidate Masoud Pezeshkian won Iran’s run-off presidential election, beating hardliner Saeed Jalili by promising to reach out to the West and ease enforcement on the country’s mandatory headscarf law after years of sanctions and protests squeezing the Islamic Republic.

Mr Pezeshkian promised no radical changes to Iran’s Shiite theocracy in his campaign and long has held Supreme Leader Ayatollah Ali Khamenei as the final arbiter of all matters of state in the country.

But even Mr Pezeshkian’s modest aims will be challenged by an Iranian government still largely held by hardliners, the ongoing Israel-Hamas war in the Gaza Strip, and Western fears over Tehran enriching uranium to near-weapons-grade levels with enough of a stockpile to produce several nuclear weapons if it chose.

A vote count offered by authorities put Pezeshkian as the winner with 16.3 million votes to Jalili’s 13.5 million in Friday’s election.

Overall, Iran’s Interior Ministry said 30 million people voted in an election held without internationally recognised monitors, representing a turnout of 49.6%, higher than the historic low of the June 28 first round vote but lower than other presidential races.

Supporters of Mr Pezeshkian, a heart surgeon and longtime politician, entered the streets of Tehran and other cities before dawn to celebrate as his lead grew over Jalili, a hardline former nuclear negotiator.

Mr Pezeshkian later travelled to the mausoleum of the late Grand Ayatollah Ruhollah Khomeini, the leader of the 1979 Islamic Revolution, and addressed journalists in a chaotic event.

“In this election, I didn’t give you false promises. I did not lie,” Mr Pezeshkian said.

“It’s been many years after the revolution that we come to the podium, we make promises and we fail to fulfil them.

“This is the biggest problem we have.”

Iranian Supreme Leader Ayatollah Ali Khamenei walks towards the ballot box
Iranian Supreme Leader Ayatollah Ali Khamenei walks towards the ballot box (Vahid Salemi/AP)

Mr Pezeshkian’s win still sees Iran at a delicate moment, with tensions high in the Mideast and a looming election in the United States that could put any chance of a detente between Tehran and Washington at risk.

Mr Pezeshkian’s victory also was not a rout of Mr Jalili, meaning he will have to carefully navigate Iran’s internal politics as the doctor has never held a sensitive, high-level security post.

Government officials up to Mr Khamenei, the supreme leader, predicted higher turnout as voting got under way, with state television airing images of modest queues at some polling centres.

However, online videos purported to show some polls empty while a survey of several dozen sites in Tehran saw light traffic and a heavy security presence on the streets.

Authorities counted 607,575 voided votes which often are a sign of protest by those who feel obligated to cast a ballot but reject both candidates.

Mr Khamenei praised the turnout on Saturday despite what he alleged was a boycott campaign “orchestrated by the enemies of the Iranian nation to induce despair and a feeling of hopelessness”.

“I would like to recommend Dr Pezeshkian, the elected president, put his trust in God, the Compassionate, and set his vision on high, bright horizons,” Mr Khamenei added.

Voters expressed a guarded optimism.

“I don’t expect anything from him — I am happy that the vote put the brake on hardliners,” said bank employee Fatemeh Babaei, who voted for Mr Pezeshkian.

“I hope Pezeshkian can return administration to a way in which all people can feel there is a tomorrow.”

Taher Khalili, a Kurdish-origin Iranian who runs a small tailor shop in Tehran, offered another reason to be hopeful while handing out sweets to passersby.

“In the end, someone from my hometown and the west of Iran came to power,” Mr Khalili said.

“I hope he will make economy better for small businesses.”

Mr Pezeshkian, who speaks Azeri, Farsi and Kurdish, campaigned on outreach to Iran’s many ethnicities.

He represents the first president from western Iran in decades — something people hope will aid the country as those in the western part are considered more tolerant because of the ethnic and religious diversity in their area.

Later on Sunday, state media reported that an outspoken Iranian lawyer who has publicly criticised how the government handled the 2022 protests over the death of Mahsa Amini has been arrested.

The unrest followed the death of the 22-year-old detained by the police for allegedly not properly wearing her mandatory hijab. The massive protests quickly escalated into calls to overthrow Iran’s four-decade Islamic theocracy.

The judiciary’s Mizan news agency said on Sunday that Mohsen Borhani had been previously sentenced but did not give further details on his case or jail time.

Mr Borhani, also a university professor, became popular on social media for his critical views of the Iranian government during the 2022 demonstrations. UN investigators said Iran was responsible for the physical violence that led to Ms Amini’s death.

The lawyer’s arrest came a day after Mr Pezeshkian was elected to lead the country.

Mr Pezeshkian promised to ease enforcement of the country’s mandatory headscarf law.