By Jonathan Head
BBC News, Bangkok
Thailand's strict lese-majeste laws protect King Bhumibol from criticism
Police in Thailand have arrested the editor of a leading political website, on charges of carrying content that threatens national security.
The Bangkok-based Prachatai website is well-known for carrying content that Thai newspapers will not publish.
The charge carries a maximum five-year jail sentence.
Thailand's reputation for media freedom has suffered in recent years, in particular through lese-majeste laws, which ban criticism of the monarchy.
Armed with an arrest warrant Thai police entered the offices of Prachatai, and detained Chiranuch Premchaiporn, the woman who founded the popular news website five years ago.
She has been charged under a new law which makes it an offence to carry computer content that endangers national security.
Freedom of expression
When asked to explain what kind of content had brought about the charge, the police refused to comment, saying it was too sensitive.
But one officer, who did not want to be named, told the BBC it was comments about the monarchy posted by readers on the website at the end of last year that were at issue.
The Thai authorities have been increasingly intolerant of perceived criticism of the monarchy in recent months.
Thousands of websites have been blocked, and a number of people charged and arrested, including a well-known academic, who fled to Britain before he could be detained.
However the use of the severe lese-majeste law has provoked widespread condemnation around the world, and a campaign by academics to have the law changed.
By instead invoking the new computer crimes law - passed just 18 months ago - the authorities may be hoping to stifle debate about the monarchy without stirring up another outcry over freedom of expression in Thailand.