Tehran Mayor Mohammad Bagher Ghalibaf quit the Iranian presidential race, backing instead hardline cleric Ebrahim Raisi in Friday's vote.
Ghalibaf, a former Revolutionary Guards commander and police chief, was one of the main challengers to President Hassan Rouhani who is seeking a second term.
"What is important now and vital is preserving the interests of the people, the country and the revolution and this cannot be achieved in any way other than a change in the current situation," Ghalibaf said, according to the Fars news agency.
"We should make a fundamental decision to create unity in the revolution’s front and I call upon all my supporters across the country to come out in support of my esteemed brother Hujjat al-Islam Ebrahim Raisi and make him succeed in forming the government of work and dignity," he added.
