Moderate cleric Akbar Hashemi Rafsanjani and reformist Mostafa Moin are heading to a run-off vote in Iran's presidential election, both camps said tonight.
Aides to the two men said Rafsanjani and Moin were the top two in a field of seven, but neither had gained the 50 per cent support needed for outright victory.
Official results are expected tomorrow.
"Rafsanjani and Moin are the first two, according to our surveys. They are the ones who will compete in the second round," close Rafsanjani aide Mohammad Atrianfar said.
"My prediction is that Rafsanjani and Moin have got the most votes and I don't think there is a huge gap between them," Mohammad Ali Abtahi, adviser to outgoing reformist President Mohammad Khatami and a strong ally of Moin.
Earlier a top Iranian official said the election of a new president would have little impact on Iran's nuclear policy, which Tehran says is to generate power but which Washington suspects is to build an atomic bomb.
Hassan Rohani, secretary of the Supreme National Security Council and leading nuclear negotiations with Europe, told the official Iranian news agency IRNA that the nuclear issue would be decided on a national level and not just by the president.
Whoever wins today’s presidential race, real power in the Islamic Republic - the world's fourth biggest oil exporter - lies with conservative anti-West religious authorities.
"The position and the characteristics of the next president would have some impact on the country's foreign policies, including the nuclear issue, but it wouldn't be as much as the Europeans and Americans think," Rohani said.
Iran has suspended uranium enrichment as part of a deal agreed with Britain, France and Germany, but has said it will not give up enrichment altogether as the Europeans demand.
The Europeans share US concerns that Iran could use the enrichment process to make material for a nuclear bomb, instead of simply making the fuel used for generating electricity.
"The stance of Iran's next president on the nuclear issue cannot be a new stance because the nuclear issue is a national issue and decision-making depends on agreements between all the country's high officials," Rohani added.