Thai authorities have charged three human rights activists with criminal defamation over a rare report describing torture suffered by detainees in the country's restive south.
Pornpen Khongkachonkiet, Anchana Heemmina and Somchai Homlaor were charged on Tuesday with defamation, which carries a two-year prison sentence, and violating the computer crimes act, which carries three years.
Rights groups said both broadly worded laws are routinely used by powerful interests to silence critics.
"All three denied the charges and will submit written testimonies later," Winyou Tiamrat, the police officer handling the case in the southern province of Pattani, said.
The report, which was based on interviews with 54 former detainees, described a host of physical and mental torture tactics allegedly used by soldiers and police.
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Beatings, threats at gunpoint, sensory deprivation and partial suffocation were all routine during detention, the report said.
The military, which denied the report's findings, has in the past admitted rights abuses but prosecutions of soldiers are extremely rare.
The rebels have also employed brutal tactics including shootings, beheadings and bombings.
Pornpen, one of those charged, said she feared her case would deter others from investigating the heavily patrolled region and push victims of abuse back into the shadows.
"We are trying hard to create a space for people [in the south] to express their grievances," she told the AFP news agency.
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Thailand is a Buddhist-majority country but the south is Muslim-majority, and resistance to Buddhist rule has existed for decades. More than 6,500 people, mostly civilians, have been killed since an uprising erupted in 2004 in the largely Muslim south.
Thailand's military junta, which came to power through a coup in 2014, has failed to revive peace talks with the rebels.
Observers say peace is unlikely while a tight security net remains over the region.