AFP - Thousands of protesters staged a protest on Thursday around a major open-air prayer venue in Tehran despite a ban on an opposition mourning ceremony there and a police crackdown, witnesses said.
  
Police moved in as crowds massed around the Grand Mosalla in the centre of the capital where religious functions are regularly held, one witness said.
  
"Protesters were raising their arms and flashing victory signs as police tried to disperse them," another said.
  
Earlier witnesses estimated the number of protesters at around 3,000, but some said the number was growing.
  
Hundreds of motorists also sounded their car horns, a protest tactic regularly used by supporters of opposition leader Mir Hossein Mousavi.
  
"Some protesters also set fire to roadside rubbish bins, while anti-riot police on motorbikes rode into the crowds in an attempt to disperse them," a witness said.
  
"Police also smashed window panes of several cars," he added.
  
Thousands of protesters were also marching on central Tehran's prominent Vali Asr Street shouting slogans such as "Death to the dictator!", "Ya Hossein! Mir Hossien!" and "Free the political prisoners!"
  
"With thousands of people walking on the street along with hundreds of motorists sounding their car horns... there is a massive traffic jam on Vali Asr," another witness said.
  
Vali Asr Street runs through Tehran from north to south and has seen regular protests against the disputed re-election of Mahmoud Ahmadinejad as president last month.