Iran's President Hassan Rouhani receives the presidential mandate from Iran's Supreme Leader Ayatollah Ali Khamenei during an endorsement ceremony, in Tehran, Iran, August 3, 2017. (Reuters photo)

TEHRAN, Aug. 3 (Xinhua) -- Iran's supreme leader Ayatollah Ali Khamenei on Thursday endorsed Hassan Rouhani as the President of the Islamic republic for his second term.

In a ceremony broadcast live on state television, Khamenei gave his official approval for Rouhani.

The incumbent moderate president won a landslide victory on May 19 by garnering 57 percent of the ballots.

His nearest conservative challenger Ebrahim Raisi got 38.5 percent of the ballots.

The key political achievement of Rouhani during past four years in the office was signing a nuclear deal with six major world powers, namely Britain, China, France, Germany, Russia and the United States, which put an end to a decade-long dispute over the country's sensitive nuclear program.

The deal, known as the Joint Comprehensive Plan of Action (JCPOA), was signed in July 2015 and was implemented in January 2016.

Based on the deal, nuclear-related sanctions on various Iranian business and financial sectors were lifted, but it put more strict limits on its nuclear program.

Rouhani will take the oath of office in the parliament on Saturday.