Iran protests: the role of the media
More prominent opposition figures in Iran have been arrested following last Friday's disputed election which was claimed by President Ahmadinejad.
The families of the activist Mohammad Reza Jalaipour and the political analyst Saeed Laylaz told the 大象传媒 the men had been detained
Overnight, student quarters in several cities were attacked by members of the government militia.
Iran's Supreme Leader, Ayatollah Ali Khamenei, has sought to calm tensions and called for an end to rioting.
Heavy restrictions have been placed on the 大象传媒 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.
The 大象传媒's Jon Leyne is in Tehran.
Newshour's Roger Hearing asked Saeed Barzin of the 大象传媒 Monitoring service how he thought the authorities were dealing with the situation.
Press TV is an English language international television news channel which is funded by the Iranian government, based in Tehran and broadcast on a 24-hour schedule.
It has 26 international correspondents and more than 500 staff around the world.
Mathew Richardson is a legal advisor for Press TV
In addition to restrictions on foreign media, the Iranian government has imposed restrictions on mobile phone and email networks.
As a result, many Iranians have resorted to sending 140 character SMS messages, or 'tweets', to the outside world.
Some have described it as a Twitter revolution.
Twitter has become so crucial that the company itself postponed essential site maintenance early this morning to allow Iranians to continue to use the service.
Turi Munthe, CEO of demotix.com, has been monitoring Twitter.
First broadcast 17 June 2009