Thailand crisis explained - in 60 seconds
Anti-government activists want Prime Minister Yingluck Shinawatra to step down and the political system to be reformed.
Thailand's main opposition party has petitioned the Constitutional Court to annul the results of 2 February's general election, saying it violated the constitution as it was not completed in one day.
The government blames opposition polling station blockades for the delays.
Here is the background to the crisis - in 60 seconds.
Video produced by Michael Hirst