BANGKOK • A Thai man who "liked" a doctored photo of the country's king on Facebook is being held incommunicado at a military base, the ruling junta said yesterday, as rights groups warned he risked becoming another victim of "enforced disappearance".

Thanakorn Siripaiboon, 27, was arrested earlier this week and charged with sedition, lese majeste and computer crimes for clicking "like" on a photo of the King and sharing it, plus an infographic on a corruption scandal, with around 600 friends.

"He is under military custody," Colonel Burin Thongprapai, a junta legal officer, said, adding that he would be remanded at a military court on Monday. "He is well and in good condition," he said.

Under Thai law, anyone convicted of insulting the revered but ailing 88-year-old Thai King Bhumibol Adulyadej, and the queen, heir or regent can face up to 15 years in jail on each count.

Prosecutions have soared since the army, which tags itself as the champion of the monarchy, grabbed power last year.

In the past two months, at least two people - including the celebrity fortune teller of the Crown Prince - have died in custody after being charged with lese majeste following secrecy-shrouded investigations.

Rights groups say the use of secret military detention - long employed in Thailand's insurgency-hit south - has "now become a new standard nationwide" under the junta, Human Rights Watch's Sunai Phasuk said.

"There is nothing at all to guarantee the safety of those held incommunicado in military detention... without access to their families and lawyers, and interrogated by soldiers without safeguards against mistreatment," he added.

Thai Lawyers for Human Rights, who are providing legal assistance to Thanakorn and his family, said in a statement that they had "no idea" where Thanakorn was being held and assumed he "has become a victim of enforced disappearance".

AGENCE FRANCE-PRESSE