Iran's newly elected President Masoud Pezeshkian vowed national unity and cooperation for navigating what he called a challenging path ahead after winning the election Saturday.

"Dear people of Iran, the election is over and this is just the beginning of our cooperation," Pezeshkian said in a statement.

"The difficult path ahead will not be smooth except with your companionship, empathy and trust."

"I extend my hand to you and I swear on my honor that I will not leave you alone on this path. Don't leave us alone," he added.

The reformist candidate won Iran’s runoff presidential election, besting hard-liner Saeed Jalili by promising to reach out to the West and ease enforcement of the country’s mandatory headscarf law after years of sanctions and protests squeezing the Islamic Republic.

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 Pezeshkian's modest aims will be challenged by an Iranian government still largely held by hard-liners, Israel's genocidal war on Gaza 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 recognized 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 Pezeshkian, a heart surgeon and longtime lawmaker, entered the streets of Tehran and other cities before dawn to celebrate as his lead grew over Jalili, a hard-line former nuclear negotiator.

Pezeshkian later traveled 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," Pezeshkian said. "It’s been many years after the revolution that we come to the podium, we make promises and we fail to fulfill them. This is the biggest problem we have."

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.

Pezeshkian's victory also wasn't a rout of Jalili, meaning he'll have to carefully navigate Iran's internal politics as the doctor has never held a sensitive, high-level security post.

Government officials up to Khamenei, the supreme leader, predicted higher turnout as voting got underway, with state television airing images of modest lines at some polling centers.

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.

Khamenei praised the turnout 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," Khamenei added.

Voters expressed a guarded optimism.

"I don’t expect anything from him – I am happy that the vote put the brake on hard-liners," said bank employee Fatemeh Babaei, who voted for Pezeshkian. "I hope Pezeshkian can return administration to a way in which all people can feel there is a tomorrow."