The low-key moderate candidate is leading the vote count in Iran's snap presidential election among a tightly controlled group of four candidates loyal to the supreme leader at a time of growing public frustration and Western pressure.

With over 3.8 million ballots from Friday's election counted so far, Massoud Pezeshkian won over 1,595,000 votes and his hard-line challenger, former nuclear negotiator Saeed Jalili, gained about 1,594,000, Interior ministry official Mohsen Eslami told state TV early Saturday.

While some insiders said the turnout was around 40%, lower than expected by Iran's clerical rulers, witnesses said that polling stations in Tehran and some other cities were not crowded.