BANGKOK (Reuters) - An opposition activist's claims that she was tortured in military custody were "100 percent fabricated", Thailand's ruling junta said on Tuesday, after the U.N. High Commissioner for Human Rights called for an immediate investigation.
Kritsuda Khunasen, 27, was one of hundreds of politicians, activists, academics and journalists held by the military after it overthrew the government of Prime Minister Yingluck Shinawatra in a bloodless May 22 coup.
Kritsuda was arrested five days later and detained for 29 days at an unidentified military camp, where she said she was blindfolded with duct tape, slapped, punched and hooded with a plastic bag until she passed out.
The allegations come amid muted criticism of the junta after it last week appointed an interim assembly whose members were mostly acting or retired soldiers and police. Junta leader General Prayuth Chan-ocha has promised to install a government by September and hold elections by late 2015.
"Thai authorities should immediately conduct an independent and detailed investigation into the alleged torture of Kritsuda Khunasen, and - if verified - bring the perpetrators to justice," Ravina Shamdasani, spokesperson for Navi Pillay, the U.N. High Commissioner for Human Rights, said in a statement.
The Thai military told Reuters it had investigated Kritsuda's claims and found them to be untrue.
"It is 100 percent fabricated," said Colonel Winthai Suvaree, a spokesman for the National Council for Peace and Order (NCPO), as the junta calls itself. "We checked with the officials, and no such incidents took place."
A member of the Shinawatra family's red-shirt loyalists, Kritsuda made the allegations in an interview released on YouTube on Aug. 2 after leaving Thailand to reportedly seek political asylum in an unidentified European country.
She said her hands remained tied during detention, even when she visited the bathroom. "While a female soldier stripped me naked and gave me a shower, I heard male voices near me. I felt I was sexually harassed," she said.
She said in her video interview that her interrogators asked about funding for red-shirt prisoners and weapons. She said they were probing for connections between her and self-exiled former premier Thaksin Shinawatra, who was ousted in a 2006 coup.
Most detainees were released within seven days, as stipulated under Thailand's martial law, but Kritsuda was held for more than four weeks - at her request, said Colonel Winthai.
"She asked to stay on and said the reason was that there may be some people trying to hurt her," he said. "Why would we force her to stay on? She is not a dangerous fugitive that we need to detain for a very long time."
She was released without charge on June 24.
Another NCPO spokesman questioned why Kritsuda had waited for so long after her release to report the alleged abuse, and suggested she made the claims to bolster her asylum request.
The interim assembly formed last week will appoint a 35-member cabinet and a prime minister - widely expected to be General Prayuth.
On July 25, in one of his regular Friday-night speeches on national television, Prayuth assured the international community that his government had "no policy to assault, kill, torture, rape or harm anyone".
But Kritsuda's allegations threaten to undermine those assurances and raise questions about the treatment of other detainees, said Sunai Phasuk, senior researcher on Thailand for Human Rights Watch, which on Tuesday criticized the military's "knee-jerk denial" and called for an investigation.
"Kritsuda is an important test case," said Sunai. "She is the first to break the silence. What about the others?"
On June 23, the day before her release, Kritsuda had said in interview on an army-owned television channel that she had voluntarily entered military custody and was "happier than any words can say".
But in her later YouTube interview, she said a senior officer told her to "say the right thing to make the military look good".
The detention of people without access to their families or lawyers "creates the environment for possible human rights abuses, including torture and ill-treatment," added Shamdasani of the U.N. rights body.
Additional reporting by Panarat Thepgumpanat and Pairat Temphairojana; Editing by Alan Raybould and Robert Birsel