Iranian Supreme Leader Ali Khamenei formally endowed President-elect Hassan Rouhani with executive authority on Thursday, according to Iran's official Tasnim news agency.
"Rouhani's second term in office has been formally initiated by the supreme leader," the news agency reported.
At the inauguration ceremony, Rouhani was quoted as saying that his second term in office -- which he secured in May 19 polls -- would be marked by "free access to information and free expression of opinion among all segments of society".
The president -- a member of Iran's reformist camp -- also promised to use his executive authority to "uproot poverty, fight corruption and curb inflation", according to Tasnim.
Khamenei, for his part, was quoted as saying that, "Despite ongoing attempts to isolate Iran, the nation has not been isolated and continues to cooperate with the world while also challenging the hegemonic powers."
He went on to describe the U.S. as the "most aggressive state in the world", calling on Iran's political leadership to remain steadfast in the face of perceived external threats ranged against it.
In the May 19 polls, Rouhani clinched 23.5 million votes out of some 41 million ballots cast, beating out hardline rival Ebrahim Raisi, who secured 38.5 percent of the vote.
