Mir Hossein Mousavi

Supporters of defeated Iranian presidential candidate Mir Hossein Mousavi are planning another mass rally Saturday, a day after Iran's supreme leader warned the opposition to end protests over last week's disputed election.

Mr. Mousavi is expected to address the rally in Tehran's Revolution Square. Tehran's governor, Morteza Tamadon, said the gathering is not authorized and should be canceled.

On Friday, Iran's supreme leader, Ayatollah Ali Khamenei, said if opposition leaders do not cease their protests, they will be responsible for any violence.

Ayatollah Ali Khamenei delivers his sermon in front of picture of late spiritual leader Ayatollah Khomeini, during Friday prayers, at Tehran University campus, 19 Jun 2009

In his first address since the June 12 vote, Khamenei also declared incumbent President Mahmoud Ahmadinejad the definitive winner.

In a show of defiance, people shouted "God is Great" and "Death to the Dictator" from rooftops across Tehran, hours after the ayatollah's speech.

Supporters of Mr. Mousavi have held near-daily demonstrations to denounce the election, which they say was rigged in favor of Mr. Ahmadinejad.

Iran's Council of Guardians, a powerful body that supervises the elections, has invited Mr. Mousavi and two other defeated presidential candidates, Mohsen Rezaei and Mehdi Karroubi, to a meeting Saturday to discuss their concerns. The Council has offered to conduct a partial recount of the vote, and a spokesman for the body says it has begun examining 646 complaints of irregularities.

Ayatollah Khamenei defended the legitimacy of the election in his address during Friday prayers, saying Mr. Ahmadinejad's 11 million-vote margin is too big to have been manipulated. He also attacked what he called interference by foreign powers that questioned the election outcome.

The ayatollah spoke at Tehran University. Thousands of people packed the campus and surrounding streets, with members of the crowd chanting "death to America" and "death to Britain."

Protests involving hundreds of thousands of people at times have turned violent. Iran has confirmed at least seven protesters were killed Monday during clashes with pro-government militia. Amnesty International says it has recorded at least 10 killings.

Iranian authorities cracked down on this week's demonstrations, with widespread arrests of opposition members, activists and journalists.

Video of the protests obtained by VOA's Persian News Network can be found here: 

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Some information for this report was provided by AFP, AP and Reuters.