Middle East protests: Country by country
Long-simmering unrest over the disputed 2009 presidential election boiled over again on 14 February 2011.
Thousands of people heeded calls by the two main opposition leaders to rally in the capital Tehran in solidarity with pro-democracy protests across the Middle East.
Security forces cracked down on the protest. Two people were killed and many more injured.
Rallies held in the days following, as well as on 20 February, were also suppressed. In further demonstrations on 1 March, the opposition claimed that 200 people were arrested.
However, since then, the authorities have succeeded in preventing any more large demonstrations from taking place.
Iran's complex and unusual political system combines elements of a modern Islamic theocracy with democracy. Its President, Mahmoud Ahmadinejad, is a hardliner who has said he will put down any protests.
Meanwhile, there has been speculation about the internal dynamics of the regime, after an apparent increase in tensions between President Ahmadinejad and the Supreme Leader Ayatollah Ali Khamenei.
In March 2012, Mr Ahmadinejad's support base in parliament was eroded in elections which saw conservatives allied to Ayatollah Khamenei win an extra 41 seats. The opposition Green Movement was barred from taking part.
The movement's leaders Mehdi Karroubi and Mir Hossein Mousavi were placed under house arrest in February 2011 and have not been seen in public since. Supporters of the government have been calling for them to be executed.
Iran's nuclear programme has long been regarded with suspicion in Israel and the West, as has its support for militant groups in the Middle East.