Mohsen Eslami, a representative of Iran's election commission, said on IRIB TV channel that after counting 24.5 million votes at all 58.6 thousand polling stations, Masoud Pezeshkian received 10.4 million votes.
According to him, Saeed Jalili is in second place with 9.5 million votes.
Since neither party secured 50% of the vote in the first phase, a second phase will be held on July 5, according to the Home Ministry.
"Since neither of the two candidates managed to secure 50% of the vote, a second round will be held nationwide on Friday, July 5," the local IRNA agency quoted Mohsen Eslami as saying.
Iran's presidential elections are underway due to the death of the country's former president. Former Iranian President Ebrahim Raisi was martyred in a helicopter crash in the Varzakan region on May 19.