"I ask my supporters throughout the country to use all of their potential" to elect Raisi, Ghalibaf said in a statement carried by state media.
"What is important now and vital is preserving the interests of the people, the country and the revolution and this can not be achieved in any way other than a change in the current situation", Ghalibaf said, according to the semi-official Fars news agency. "This great ideal can only be achieved by changing the status quo". Qalibaf's support could help stoke interest in Raisi, who has been described as unknown and severely lacking in charisma.
While Article 15 of the Iranian Constitution, on paper, allows Kurdish and other spoken languages to be taught in schools and higher education systems, there has been little practical progress towards such a realisation of rights since the country's 1979 revolution.
There was no immediate reaction from Rouhani.
Iranian President Hassan Rouhani's electoral campaigners have intensified publicity focusing on the segment of undecided voters, namely those of moderate views.
Iran's ultra-conservative political faction is beginning to consolidate itself behind Ebrahim Raisi, a prodigy of the country's supreme leader, in an attempt to retake the presidency in the upcoming election. More than 50 million people are eligible to vote. The poll, published last week, shows Rouhani at 42 percent and Raisi with 27 percent, but the poll was conducted before Qalibaf dropped out.
Khatami, in a video posted online, urged voters to cast their ballot for Rouhani to ensure the "implementation of social and economic justice". A Raisi victory could alarm investors and set Iran on a more confrontational course with the Trump White House - which has called the nuclear deal a "disaster" - and its Sunni Gulf Arab allies.
It was Khamenei who previous year appointed Raisi, 56, to manage the Astan Quds Razavi, an Islamic charity that controls assets worth billions of dollars, as well as the Imam Reza shrine in the northeastern holy city of Mashhad. He already has the support of two major clerical bodies that declined to endorse anyone in the last presidential election.
Farhadi's intervention came as Rouhani, who is allied with the reformists, travelled to Isfahan, Iran's popular tourist destination, to speak to tens of thousands of supporters in the city's historic Naqsh-e Jahan square. Qalibaf's endorsement may push those so far unexcited by the election into voting for Rouhani, said Cliff Kupchan, the chairman of the Eurasia Group. Qalibaf's dropping out may serve to get him more votes in his challenge to Rouhani.