Iran is expected to shift to a more hardline stance against Western countries under Ebrahim Raisi, the conservative Islamic law scholar and judiciary chief who has won the country's presidential election.
Raisi secured a crushing victory with about 62 percent of the ballots in Friday's election. He is set to take office in August.
Raisi is expected to bring in the first anti-US conservative hardline administration in eight years, changing course from current President Hassan Rouhani's policy of seeking dialogue with the West.
Raisi expressed a resolve to do his best to perform his duty for the Iranian people, after talking with the outgoing president on Saturday.
Raisi has indicated that he would maintain the nuclear agreement with world powers. Former US president Donald Trump unilaterally withdrew his country from the deal in 2018.
The US and Iran have been holding indirect talks aimed at reviving the nuclear deal since April. However, Raisi has vowed not to make any easy concessions.
More than 1,000 supporters of Raisi cheerfully celebrated his victory with fireworks in the capital, Tehran. They were holding Raisi's portrait and chanting his name.
A 27-year-old woman who voted for Raisi said she expects that the employment situation for young people will get better and the economy will be back to normal as much as possible. Iran's economy has deteriorated, partly due to US sanctions.
A 35-year-old man who abstained from the vote said nothing would change from the current situation because Raisi has an anti-US stance. He said he would like his country to at least stop antagonizing the US.