BANGKOK — Facebook is planning legal action against the government of Thailand for ordering the social media platform to partially shut down access to a group critical of the Thai monarchy, the company said Tuesday.

On Monday, Facebook began preventing users in Thailand from accessing Royalist Marketplace, a Facebook group with more than 1 million members that was set up by a self-exiled Thai academic living in Japan.

Thailand has some of the world’s strictest lèse-majesté laws, which make it a crime to criticize members of the royal family. Other legislation, including a sedition law and a computer crimes act, have also been used to target critics of the royal family, even as protesters have taken to the streets in recent weeks to call for the monarchy’s power to be curbed.

Buddhipongse Punnakanta, Thailand’s digital economy and society minister, warned this month that Facebook would be breaking the computer crimes act if it allowed Royalist Marketplace, which was founded in April, to continue operating in Thailand. The minister gave Facebook until Tuesday to restrict access to the group or pay a relatively small fine.

Facebook condemned the government’s request Tuesday and said it would ask a Thai court to revoke the order filed against the company’s Thailand operations.

“Requests like this are severe, contravene international human rights law and have a chilling effect on people’s ability to express themselves,” Facebook said in a statement. “We work to protect and defend the rights of all internet users and are preparing to legally challenge this request.”

A tense political atmosphere has coalesced in Thailand, with weeks of student-led protests calling for democratic reforms and more oversight over King Maha Vajiralongkorn Bodindradebayavarangkun. Members of the urban middle class have been drawn to the demonstrations, with more than 10,000 people gathering at Democracy Monument earlier this month.

The protesters have criticized the government and called for reforms to the monarchy. Prime Minister Prayuth Chan-ocha, a former general, came to power in 2014, after orchestrating a military coup that he said was necessary to protect the palace from naysayers.

“The actions we took,” Prayuth said Tuesday in reference to Facebook, “are in accordance with Thai law, not using dictatorship powers.”

“If they sue us, we have to use the Thai law to fight,” he added. “We don’t go against other countries’ laws.”

But others accused Thailand of going against international norms on freedom of speech.

“Thailand’s government is again abusing its overbroad and rights-abusing laws to force Facebook to restrict content that is protected by the human right to free speech,” said John Sifton, the Asia advocacy director at Human Rights Watch, in a statement. “It is Thailand that is breaking the law here, international law protecting freedom of expression.”

The king, whose father was the world’s longest-reigning monarch when he died in 2016, spends most of his time outside Thailand. Critics have asked why he is rarely in the country, especially at a time when Thailand is facing its worst economic contraction in decades amid the coronavirus pandemic.

Previous Thai governments have periodically blocked online content deemed critical of the monarchy. Critics of the palace and the military-aligned government have been jailed. Hundreds of others have been forced to undergo indoctrination sessions run out of military bases.

A number of protest leaders have been arrested on charges of sedition and other crimes, with the latest round of arrests coming Tuesday. Other dissidents have disappeared entirely.

Last week, the Ministry of Digital Economy and Society filed a cybercrime complaint against Pavin Chachavalpongpun, the academic who is the administrator of the Royalist Marketplace group. For years, Pavin had been a rare Thai voice calling for frank discussions of the monarchy’s role in modern Thai society.

On Monday evening, after access to Royalist Marketplace was restricted by Facebook, Pavin created a new group with a similar name. That Facebook group, which is still accessible in Thailand, now has nearly half a million members.

“I never thought that I would be the founder of the fastest-growing social group in Thailand,” Pavin said in an interview. “Going through the membership, I realize this is not just young people, but laypeople, middle-aged people, so many people in Thailand who just want the right to speak about the monarchy openly.”

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