Iran's new President Hassan Rouhani took the oath before parliament at a ceremony attended for the first time by foreign dignitaries including regional leaders.
Rouhani, who replaces Mahmoud Ahmadinejad, was sworn in during an open session of parliament on Sunday. State TV broadcast the ceremony live.
The ceremony in parliament took place on Sunday, a day after Rouhani was formally endorsed by Iran's supreme leader, Ayatollah Ali Khameini, Yesterday's event was attended by top Iranian figures including outgoing president, Mahmoud Ahmadinejad.
Leaders and other representatives from more than 50 countries, mostly from the region, were presemt at today's ceremony.
It was the first time since Iran's 1979 Islamic Revolution that foreign dignitaries attended the swearing-in ceremony of an Iranian president, underscoring Rouhani's stated commitment to improving the country's foreign ties.
Rouhani won a landslide victory in June 14 presidential elections.
Rouhani nominated Iran's former ambassador to the United Nations Mohammad Javad Zarif as foreign minister on Sunday and picked Bijan Zanganeh to return to the post of oil minister which he held under the reformist government from 1997 to 2005.
The cabinet nominations have to be approved by parliament.
The speaker of parliament said the assembly would review the nominees in the next week.
The White House congratulated the Iranian people for "making their voices heard" and encouraged Rouhani to work towards a solution over Iran’s nuclear program.
"The inauguration of President Rouhani presents an opportunity for Iran to act quickly to resolve the international community's deep concerns over Iran's nuclear program," said Obama administration press secretary Jay Carney in a statement.
"Should this new government choose to engage substantively and seriously to meet its international obligations and find a peaceful solution to this issue, it will find a willing partner in the United States."
Al Jazeera and wire services