Iranian vice president pulls out of poll, backs Rouhani

Mayor of Tehran Mohammad Baqer Qalibaf, a figure in the principlist political faction who struggled to drum up support for his presidential campaign by hammering President Hassan Rouhani, chose to quit the race on Monday in favor of Raisi.

Jahangiri registered to run for the election amid concern among Rouhani's allies that the president might be disqualified by the Guardian Council, a clerical body that vets candidates based on their loyalty to the Islamic Republic. If the then six-candidate field was reduced to the pair, 48 percent of respondents would vote for Rouhani and 39 percent for Raisi, according to the survey released on May 10.

"Not all of Qalibaf's supporters will move to Raisi, but he does provide some capacity for conservatives to unite", said Suzanne Maloney, an Iran scholar at the Brookings Institution in Washington.

"I will vote for Mr Rouhani in the presidential election", Jahangiri said as he announced he was withdrawing his candidacy.

Over 56 million Iranians are eligible for balloting on decisive Friday.

Rouhani has warned his supporters that Qalibaf and Raisi, whose backgrounds are in the Revolutionary Guards and Iran's hardline judiciary, will take the country back to "extremism".

In the last election four years ago, Qalibaf finished second but with just 16.5 percent of the vote.

The election is largely viewed as a referendum on the 2015 nuclear deal struck with world powers shepherded by Rouhani's administration.

A Raisi victory could put Iran on a more confrontational course with the West - and in particular President Donald Trump, who visits Iran's chief regional rival, Saudi Arabia, this week.

Raisi, a cleric and former attorney general, serves as the head of the Imam Reza charity foundation, which manages a vast conglomerate of business and endowments in Iran. Raisi has been campaigning on that, proposing populist cash payments for the poor that have proven popular in the country in the past under Ahmadinejad.

Raisi's candidacy has revived the controversy surrounding Iran's mass execution of thousands of prisoners in 1988, one of the darkest chapters of the country's history since the 1979 revolution and an event still not acknowledged by authorities.

That past has anxious moderates and reformists in Iran.

Qalibaf had been under pressure from fellow hard-liners to fall in behind Raisi.

"It's definitely more hard for Rouhani now", said Aniseh Bassiri Tabrizi, a research fellow at the Royal United Services Institute in London.