Foreign reporters in Iran have been forbidden to attend opposition rallies protesting at the results of last week's disputed presidential election - but Iranians are using technology to get the story out.
Iranians are supplying reports of protests using mobile phones and the internet.
United States President Barack Obama is resisting pressure to side publicly with the political opposition in Iran, though the US State Department has asked social networking site Twitter to delay planned maintenance work so Iranians can stay in touch with each other and people outside Iran.
State Department spokesperson Ian Kelly says such websites are empowering the Iranian people.
Authorities in Iran have shut down websites, including Facebook, and clamped down on text messaging in an attempt to bring the protests under control.
Another day of mass protest is planned to begin in Iran on Wednesday, with a big demonstration to be held in the capital Teheran.
The Iranian opposition, led by moderate Mir Hossein Mousavi, is continuing its show of defiance against the government of President Mahmood Ahmadinajad, triggered by the disputed presidential election.
U-turn on recount
Iran's powerful Guardian Council says it is now prepared to recount disputed votes from Friday's poll.
Official figures show Mr Ahmedinejad won almost 63% of the presidential vote, but Mr Mousavi has contested the result, alleging widespread fraud.
Mr Mousavi is calling for the entire election to be re-run. His supporters say a recount would be meaningless because they suspect millions of ballots have disappeared.
The official results sparked three days of huge protests and Iranian radio is reporting that seven people were killed during demonstrations on Monday. The rally was described as the biggest demonstration in the Islamic republic's 30-year history and a "political earthquake".
The Guardian Council - Iran's supreme legislative body - says votes will be recounted in areas contested by the losing candidates.
Mr Obama says he is deeply troubled by the violence in Iran and has called on the leadership there to respect free speech and the democratic process.
He said the world was inspired by the Iranian demonstrators who have taken to the streets, but his administration will continue to pursue direct dialogue with the country's government.
Meanwhile, Mr Ahmadinejad is making his first international appearance since the disputed election. He is visiting the Russian city of Yekaterinburg for a meeting of the Shanghai Co-operation Organisation, a regional security group bringing together Russia, China and four central Asian states. Iran has observer status at the summit.
Before leaving, Mr Ahmadinejad made a statement to reporters that contained no reference to the protests against him.