Iranian riot police and opposition supporters clashed in Tehran Monday, hours after Mahmoud Ahmadinejad was endorsed as president for a second term.
A correspondent for Iran's state-run Press TV says riot police used tear gas to disperse about 2,000 demonstrators who gathered between Valiasr and Vanak Squares in the capital.
Iran has barred foreign news organizations from sending reporters to cover opposition protests.
Earlier, Iran's supreme leader formally endorsed the second-term presidency of Mahmoud Ahmadinejad, despite opposition claims of fraud in his re-election.
Ayatollah Ali Khamenei approved Mr. Ahmadinejad's presidency at an official ceremony Monday in Tehran. Several hundred people were present, but there were notable absences including two former presidents, Mohammed Khatami and Akbar Hashemi Rafsanjani. Defeated reformist candidates, Mir Hossein Mousavi and Mehdi Karroubi, also did not attend the event.
The supreme leader Monday praised the election's outcome. Mr. Ahmadinejad will be sworn in by parliament on Wednesday.
The president has two weeks from that date to announce his new Cabinet.
After Mr. Ahmadinejad's first election four years ago, a photograph was circulated of the new president kissing Khamenei's hand in a show of loyalty. But this year, Iranian media report the supreme leader stepped back when Mr. Ahmadinejad approached in an apparent attempt to kiss his hand Monday. The ayatollah instead allowed the president to kiss his shoulder.
After the June 12 presidential election, Iranian security forces arrested hundreds of activists, politicians and protesters. A mass trial for more than 100 of the detainees began Saturday.
Former President Khatami, who now heads one of the largest reform parties in Iran, said Sunday the mass trial is unconstitutional.
He called the judicial proceedings a "show" trial, and said prosecutors are relying on confessions that were illegally obtained.