Iranian riot police used teargas on protesters, fired guns into the air and bundled several people into police buses today as thousands of Mousavi supporters defied a warning from the authorities that any new protests would be "smashed".
Witnesses told the Guardian and other news organisations that security forces moved quickly to disperse the latest rally, which was called to mark the 10th anniversary of student riots that until the recent street demonstrations had been the worst unrest since the 1979 revolution.
Police fired shots in the air above the crowd and swooped to arrest at least 10 protesters at one location in Tehran, a witness said. One elderly man was pushed to the ground, handcuffed and put in a police bus after he shouted: "Death to the dictator." Another witness reported clashes in another part of the city.
The police stopped the cars of those supporting the protest and confiscated driving licences, a second witness said.
"Riot police have just blockaded access of protesters to approach Tehran University and are threatening people by beating them up with plastic and electronic batons, trying not to let them gather in groups," said Jamshid, 25, a university student at the rally.
"Protesters are shouting Allahu Akbar [God is greatest] in other streets near Enghelab Square. The interesting point is that the government don't have enough people this time in streets because they need to control provinces as well, as today protest is not just limited to Tehran and is also taking place in other big cities."
Footage of today's protests posted on YouTube showed crowds of men and women chanting and making victory signs. Many of them wore face masks.
The demonstrations have been the biggest since street protests fizzled out two weeks ago in the face of a deadly crackdown by the security forces and pro-regime militias. Today, further grim video footage emerged showing how one protester, Davood Sadrieh, died of gunshot wounds during one of the first confrontations between troops and protesters last month.
Supporters of Mir Hossein Mousavi, the defeated opposition presidential candidate, had been exhorted in emails and Facebook messages to come out in mass protests in Tehran and other major cities such as Isfahan, Shiraz and Tabriz, apparently in an attempt to make it hard for security forces to focus their efforts.
Witnesses said protesters gathered at Enghelab Street near Tehran University, a focal point for last month's rallies that brought hundreds of thousands on to the streets. Other protesters headed for the central rallying point from six of Tehran's biggest squares.
The governor of Tehran warned that security forces would not hesitate to crush any protests. "If some individuals … listen … to a call by counter-revolutionary networks they will be smashed under the feet of our aware people," said Morteza Tamaddon.
Tamaddon said there had been no request for a permit to stage protests. Iranian authorities have repeatedly used the lack of a permit as a pretext for stifling dissent.
Other apparent counter-measures included a block on mobile phone text messaging for a third consecutive day, supposedly to prevent communication between protesters, and the closure of the universities. Tuesday and Wednesday were declared official holidays, ostensibly because Tehran was shrouded in a heavy cloud of dust and pollution.
Unprecedented mass protests erupted after Mahmoud Ahmadinejad, the incumbent president, was declared the winner of the 12 June vote. Mousavi and Mehdi Karroubi, another defeated reformist candidate, both insist the election was rigged. Demonstrations have faded away in the last 10 days after the authorities banned rallies and rounded up protesters, political activists and journalists.
Ahmadinejad has defended the election as "the most free held anywhere in the world".
At least 20 people were killed in clashes with the security forces and the pro-government basij militia. In all, more than 1,000 people were reportedly arrested. The prosecutor general said yesterday that 500 would be tried, possibly contradicting official claims that "most" had already been freed.
Tamaddon blamed the trouble on interference by foreign broadcasters. "The enemies of the Iranian nation are angry with the post-election calm in Iran and try to damage it through their TV channels," he said, according to Press TV, a state-run broadcaster.
The 1999 protests being marked today were during the rule of the reformist president Mohammed Khatami. The closure of a newspaper that supported him triggered protests that turned violent with an attack on a student dormitory at the University of Tehran by riot police and paramilitary forces. Khatami now backs Mousavi.
