Moussavi used a posting on his website Sunday night to call on own supporters to demonstrate peacefully despite warnings from Iran’s supreme leader Ayatollah Ali Khamenei that no protests of the vote would be allowed.

“Protesting to lies and fraud is your right,” Moussavi said.

In an apparent response, the Revolutionary Guards told demonstrators on Monday to “end the sabotage and rioting activities”, calling their protests a “conspiracy” against Iran.

Foreign Ministry spokesperson Hassan Qashqavi called the turnout a “brilliant gem which is shining on the peak of dignity of the Iranian nation”. He accused Western powers and news organisations of spreading unacceptable “anarchy and vandalism.”

On Sunday, the police detained five relatives of Ali Akbar Hashemi Rafsanjani, who openly supported Moussavi. The relatives, including Rafsanjani’s daughter, Faezeh Hashemi, were released after several hours.

In the network of Internet postings and Twitter messages, a powerful and vivid new image emerged: a video posted on several websites that showed a young woman, called Neda, her face covered in blood. Text posted with the video said she had been shot.

The website of reformist candidate Mehdi Karoubi referred to her as a martyr who did not “have a weapon in her soft hands or a grenade in her pocket but became a victim by thugs who are supported by a horrifying security apparatus”.