Hundreds of supporters of Iranian opposition leader Mir Hossein Mousavi chanted "death to the dictator" in Tehran tonight, a witness said, a day after Mahmoud Ahmadinejad sworn in as president.
"Hundreds of people are in Vanak square, chanting 'death to the dictator'. Others are also honking car horns," said the witness. "Hundreds of riot police are there as well."
Mr Ahmadinejad took the oath of office nearly eight weeks after a disputed election that unleashed the biggest anti-government protests since the 1979 Islamic revolution and divided the political and clerical elite.
Riot police were posted at Tehran's main squares today to prevent any gathering by Mousavi supporters.
Mousavi and the other defeated pro-reform candidate Mehdi Karoubi say the next government will be illegitimate - defying Supreme Leader Ayatollah Ali Khamenei, who has formally endorsed Ahmadinejad.
The witness said riot police tried to disperse protesters. "They are telling protesters to leave the area or face being arrested," the witness said.