Facebook says plans to challenge Thai government demand to block group critical of monarchy

BANGKOK (Reuters) - Facebook <FB.O> said on Tuesday it was planning to legally challenge the Thai government after being "compelled" to block access within Thailand to a group with 1 million members that discusses the country's king.

The social media giant late on Monday blocked access to the "Royalist Marketplace" group after the Thai government threatened legal action over failure to take down content deemed defamatory to the monarchy.

"Requests like this are severe, contravene international human rights law, and have a chilling effect on people's ability to express themselves," a Facebook spokesperson said in a statement to Reuters.

"We work to protect and defend the rights of all internet users and are preparing to legally challenge this request."

The statement did not give details on the legal challenge. Insulting the monarchy is illegal in Thailand.

(Reporting by Patpicha Tanakasempipat; Editing by Ed Davies)