Amnesty International has vowed to continue to investigate torture and abuse in Thailand after being forced to cancel a press conference on Wednesday morning to release details of a report into widespread allegations.
Authorities blocked Amnesty from releasing the report, threatening legal action against any speakers under Thailand's labour laws.
"It is an appalling state of affairs when speaking up for human rights can be criminalised but torture continues with impunity,” said Minar Pimple, Amnesty International’s senior director of global operations.
About seven police arrived at the Sukhumvit hotel where the event was to be held at 9am, half an hour before it was to begin.
Negotiations to allow the event to go ahead failed.
Amnesty was to have launched the report, “Make Him Speak by Tomorrow: Torture and Other Ill-Treatment in Thailand”. It details 74 instances of torture and other ill-treatment at the hands of soldiers and the police against suspected insurgents, government opponents and other individuals from vulnerable backgrounds.
“The Thai authorities should be addressing torture, not human rights activists doing their legitimate work," Mr Pimple said. "Instead of threatening us with arrest and prosecution, they should be holding the perpetrators of torture accountable."
He said they were simply told that the event could not proceed.
"The authorities claimed that they were not shutting the event down itself, but at the same time warned that if representatives of Amnesty International spoke at the event, they could be subject to arrest and prosecution under Thailand’s labour laws,” Mr Pimple said.
“We had no advance warning of this. We have engaged the Thai authorities in a constructive manner since the outset of this work on torture and other ill-treatment in the country.
"Before coming to Thailand to launch the report, we also shared our findings with the authorities, writing to the Prime Minister and other key ministers.”
"We will deliver the report one way or another," said Yuval Ginbar, a London-based human rights activist who has a one-year business visa for Thailand valid until December 2016. "We are not able to continue with today's event."
Mr Ginbar was to have been joined on stage by Rafendi Djamin, director of Amnesty South East Asia and the Pacific Regional Office, based in Bangkok, and Laurent Meillan, officer in charge, United Nations Human Rights Office for Southeast Asia.