Ex-Iranian President Mahmoud Ahmadinejad reacts as he submits his name for registration as a candidate in Iran's presidential election, in Tehran, Iran April 12, 2017. [Photo/Agencies]

During the registration in Iran's Interior Ministry, Ahmadinejad, expressed hope for victory.

He vowed to serve the Iranians, and try hard for the establishment of "justice and freedom" if he is reelected as the president.

Ahmadinejad was accompanied by his confidant former controversial deputies Hamid Baqaee and Rahim Mashae. Baqaee also registered for the presidency.

In Sept. 2016, local media quoted Iran's Supreme Leader as saying that "I do not find it advisable that you (Ahmadinejad) participate" in the next presidential elections.

The former hardline president, Ahmadinejad, was a two-term president for 8 years, before President Hassan Rouhani took the office in 2013 election.

On Tuesday, Iran's Interior Minister Abdolreza Rahmani Fazli announced registration of candidates for Iran's 12th presidential race began in capital Tehran.

The registration will last for five days and all the hopefuls will undergo the subsequent vetting process by the country's high legislative body, namely the Guardian Council of the Constitution.

The Guardian Council will assess the qualification of the applicants and announce the names of the qualified candidates by April 27.

According to the schedule released by Iran's Interior Ministry, the campaign for presidential race will kick off on April 28 and will continue until the end of May 17.

The hopefuls will have 20 days for electoral campaigns, ahead of the election day slated for May 19.

The candidate should basically be an Iranian national, prudent and capable of taking on leadership duties, and being religious and believing in the Islamic republic's principles and its official religion.