The situation, however, was brought into focus by the reports that the Supreme Leader - who had been in his post since 1989, after serving as President - was now terminally ill.
"Raisi's lifestyle is modest and he regularly stays with the poor sections of society, while Mr Rouhani has more of an aristocratic, comfort-seeking spirit", said Hamid Reza Taraghi, a member of the conservative Islamic Coalition Party.
Former Iranian President Mahmoud Ahmadinejad said the recent United States missile strike on Syria did not faze him in a recent interview with the Associated Press.
He urged the Iranians, particularly, the youngsters, to actively participate in the upcoming presidential elections.
He sought to reach across political lines on Friday, saying: "I will be the candidate for the whole of Iran".
He previously served positions in Iran's Judiciary, as the Attorney General from 2014 to 2016, and Deputy Chief Justice from 2004 to 2014 for ten years. The Aradan native proceeded to register anyway, and although the Ayatollah has the final say it does not look good in terms of Mahmoud Ahmadinejad's respect for authority.
Ahmadinejad, who flashed a V for victory sign as he registered April 12, was embroiled in conflicts with officials during his second term and his entry is seen in apparent defiance of Khamenei, who had asked that he doesn't run to avoid polarizing the country.
Influential Shi'ite cleric Ebrahim Raisi, the custodian of a powerful organization in charge of Iran's holiest shrine, appears to be the leading hardline candidate.
Iran's President Hassan Rouhani participated Saturday in an exhibition displaying the achievements of the Defense Ministry gained during the past two years, IRNA reported April 15.
The registration process, which opened on April 11, is set to conclude on Saturday.
Most of the analysts believe that Rouhani, Raisi and Ahmadinejad will be the three major candidates with political weight and ideological reflection, whose competition can heat up the furnace of election in Iran next month.
Rouhani won in a single round with more than 50 percent of the vote in 2013 when no other candidate took more than 17 percent, but may face a tougher campaign this time if often-feuding hardliners can join forces against him.
Rouhani has on several occasions called for massive turnout in the elections slated for May 19.
Rouhani made his remarks at a ceremony in the Iranian capital of Tehran that displayed a number of achievements in the Islamic Republic's defense industry, among which included the the Qaher F-313 fighter jet, the Nasir anti-ship cruise missile and the Fakur air-to-air missile.