Rouhani’s election was endorsed by the country’s supreme leader Ayatollah Ali Khamenei yesterday at a ceremony in the capital, Tehran.
The cleric, who won the presidential poll in June, has promised reform and to end Iran’s international isolation. While his term officially started yesterday, his public inauguration will take place today.
The 64-year-old is a former nuclear negotiator for Iran and was an Islamic activist before the country’s 1979 revolution. He studied at Glasgow Caledonian University in the mid-1990s.
He met Khameini at a mosque in Tehran to receive his formal endorsement yesterday. The ceremonial event was attended by top Iranian figures including Ahmadinejad, and foreign dignitaries.
The ceremonies come after Rouhani marked Quds Day (Jerusalem Day) on Friday with a speech showing solidarity with Palestinians amid mass rallies in Tehran.
“In our region there’s been a wound for years on the body of the Muslim world under the shadow of the occupation of the holy land of Palestine and the beloved al-Quds [Jerusalem],” Rouhani said in comments broadcast on state TV.
“This day in actuality is a reminder that Muslims will not forget their historic right [to Jerusalem] and will continue to stand against aggression and tyranny.”
Also on Friday, addressing a large crowd at Tehran University, Ahmadinejad warned that a regional storm was brewing that would “uproot” Israel.
Ahmadinejad said in a speech also broadcast on state television: “I will inform you, with God as my witness, that a devastating storm is on the way that will uproot the basis of Zionism.”
He added that Israel “has no place in this region”.
Rouhani has the support of Iran’s reform movement, which wants the president to enact real change – including the release of political prisoners and the lifting of international sanctions that have hurt the country’s economy. But while he may be president, he will not be Iran’s main decision-maker.
Rouhani’s remarks echo comments on Quds Day from other Iranian leaders dedicated to supporting the Palestinians and denouncing Israel.
Iran has denied Israel’s right to exist since the 1979 Islamic revolution.
Many Iranians believe Ahmadinejad has put Iran on the path to economic ruin and confrontation with the outside world.
Last week, the Obama administration signalled its hopes for an easing of nuclear tensions by declining to publicly back tough new sanctions on Iran approved by the US House of Representatives.