U.S President Barack Obama has called recent post-election violence against protesters in Iran "outrageous."
He spoke at a joint White House appearance with German Chancellor Angela Merkel. Mr. Obama said Iranian people have the universal right to assemble and to speak freely.
Earlier in Italy, foreign ministers from the world's main industrialized countries, the Group of Eight, issued a statement deploring the violence, which led to the loss of civilian lives.
Groups of Iranians visited a Tehran cemetery Friday and released green balloons to pay tribute to a young woman named Neda Agha Soltan they say was killed by Iranian security forces.
The official death toll from violence since the disputed June 12 election is 17, but witnesses say it is much higher. Green has been the color used by supporters of defeated candidate Mir Hossein Mousavi.
In a sermon at Tehran University, a senior Iranian cleric, Ahmad Khatami, described the demonstrators as rioters who, in his words, wage war against God, a crime under Islamic law, and punishable by death.
The street demonstrations that initially took place nearly every day following the election have largely subsided due to a heavy police presence.
In the Swedish capital, Stockholm, though, angry protesters threw stones and rushed the gates of the Iranian embassy.
Meanwhile, Iran's Guardian Council has rejected allegations of fraud, calling the June 12 presidential poll the cleanest vote the country has ever had.
The official IRNA news agency said Friday the Guardian Council found no major violations in the vote which declared incumbent President Mahmoud Ahmadinejad the winner by a large margin.
Both the Guardian Council and Iran's Supreme Leader Ayatollah Ali Khamenei have said the results will not be annulled.
Iran's crackdown has included heavy restrictions on reporting and the arrest of university professors, journalists and ordinary citizens.
Some information for this report was provided by AP and Reuters.