The reformist candidate Masoud Pezeshkian’s lead against hardliner Saeed Jalili widened early on Saturday to over 2m votes as counting continued in Iran’s presidential runoff election. 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 former nuclear negotiator close to Iran’s supreme leader. Mohsen Eslami, an election spokesperson, said Pezeshkian had 11.1m votes, leading Jalili’s 9m. He gave no total turnout figure as counting went on. The first round of voting on 28 June saw the lowest turnout in the history of the Islamic Republic since the 1979 revolution. Iranian officials have long pointed to turnout as a sign of support for the country’s Shia theocracy, which has been under strain after years of sanctions crushing Iran’s economy, mass demonstrations and intense crackdowns on all dissent. Government officials up to the supreme leader, Ayatollah Ali Khamenei, predicted a higher participation rate as voting got under way, with state television airing images of modest lines at some polling centres. However, online videos purported to show some polls empty while a survey of several dozen sites in the capital, Tehran, saw light traffic amid a heavy security presence on the streets. More than 61 million Iranians over the age of 18 were eligible to vote, with about 18 million of them between 18 and 30. Voting was to end at 6pm but was extended until midnight to boost participation. The late president, Ebrahim Raisi, who died in a May helicopter crash, was seen as a protege of Khamenei and a potential successor as supreme leader. While Khamenei remains the final decision-maker on matters of state, whichever man ends up winning the presidency could bend the country’s foreign policy towards either confrontation or collaboration with the west. Many knew Raisi for his involvement in the mass executions that Iran conducted in 1988, and for his role in the bloody crackdowns on dissent that followed protests over the 2022 death of Mahsa Amini, a young woman detained by police over allegedly improperly wearing the mandatory headscarf, or hijab. In April, Iran launched its first ever direct attack on Israel, while militia groups that Tehran arms in the region – such as the Lebanese Hezbollah and Yemen’s Houthi rebels – are engaged in the fighting and have escalated their attacks. Iran is enriching uranium at near weapons-grade levels and maintains a stockpile large enough to build several nuclear weapons, should it choose to do so. The campaign also repeatedly touched on what would happen if Donald Trump won the November election in the US. Trump withdrew America from the Iran nuclear deal in 2018. Iran has held indirect talks with Joe Biden’s administration, although there has been no clear movement back towards constraining Tehran’s nuclear programme in return for the lifting of economic sanctions.