Demonstrators flocked to the streets of cities around the world on Saturday, including in Canada, to demand Iran's rulers end the persecution and imprisonment of opposition activists following the country's disputed presidential election.

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Protesters take part in a rally against the Iranian regime and to demand the release of all political prisoners, as part of a global day of action event in Stockholm on Saturday. ((Fredrik Persson/Scanpix/Reuters))

Large events were held in Stockholm, Berlin, Paris, Amsterdam and London, while in Toronto, cyclists, marchers and others planning a 24-hour hunger strike gathered outside the Ontario legislature bearing billowing red flags and lime green placards calling for Iranians' human rights to be respected.

Halifax, Montreal and Vancouver also held marches on Saturday, organized by groups including Human Rights Watch and Amnesty International as part of a  global day of action.

The worldwide protests came as media reports quoted witnesses as saying Iranian police and pro-government militia attacked and scattered hundreds of protesters in the streets of Iran's capital, Tehran.

One of the witnesses said the protests were in response to demonstrations held around the world on Saturday.

Protesters in Tehran's Vanak and Mirdamad districts reportedly chanted "death to the dictator" and "we want our vote back" before they were attacked and beaten by police, according to the witnesses.

The Iranian regime has barred most foreign media from working in the country, making it difficult to verify reports of more demonstrations.

Iranian opposition leader Mir Hossein Mousavi has refused to accept the results that acclaimed hardline incumbent President Mahmoud Ahmadinejad the victor of the June 12 vote.

Police, Revolutionary Guards and the pro-Ahmadinejad volunteer Basij militia arrested more than 2,500 people in their heavy crackdown on protests that erupted in support of Mousavi after the disputed election.

More than 500 remain in prison, including many top politicians from pro-reform political parties, human rights lawyers, journalists and activists.

Arrests have continued in recent weeks, while Mousavi has demanded another vote and decried the Ahmadinejad government as illegitimate.

With files from The Canadian Press