The Iranian Revolutionary Guard, the country's most powerful military force, has warned demonstrators against further protests over the disputed election.
On its website, the Guard said protesters would face what it called a "revolutionary confrontation".
Eyewitnesses said riot police had used tear gas earlier today to disperse hundreds of demonstrators in the centre of Tehran.
Heavy restrictions have been placed on the BBC and other foreign news organisations.
Reporters are not allowed to cover unauthorised gatherings or move around freely in Tehran -- but there are no controls over what they can say.
First broadcast 22 June 2009
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