Updated

President Mahmoud Ahmadinejad asked Iran's cleric-controlled judiciary on Monday to investigate the killing of Neda Agha Soltan, who became an icon of Iran's ragtag opposition after gruesome video of her bleeding to death on a Tehran street was circulated worldwide.

Ahmadinejad's Web site said Soltan was slain by "unknown agents and in a suspicious" way, convincing him that "enemies of the nation" were responsible.

The regime has implicated protesters and even foreign intelligence agents in Soltan's death. But an Iranian doctor who said he tried to save her told the BBC last week she apparently was shot by a member of the volunteer Basij militia. Protesters spotted an armed member of the militia on a motorcycle, and stopped and disarmed him, Dr. Arash Hejazi said.

Authorities have cracked down hard on dissent, most recently on Sunday, when riot police clashed with up to 3,000 protesters near the Ghoba Mosque in north Tehran. It was Iran's first major post-election unrest in four days.

Witnesses told The Associated Press that police used tear gas and clubs to break up the crowd, and said some demonstrators suffered broken bones. They alleged that security forces beat an elderly woman, prompting a screaming match with young demonstrators who then fought back.

The reports could not be independently verified because of tight restrictions imposed on journalists in Iran.