UN expert says torture continues at Guantanamo Bay

An independent UN human rights investigator said on Wednesday that he had information about an inmate being tortured at the US Guantanamo Bay detention facility, despite Washington banning "enhanced interrogation techniques" almost 10 years ago.

The US Department of Defence denied the allegation, saying there was no credible evidence to support it.

Nils Melzer, the UN special rapporteur on torture, said he had information that Ammar al-Baluchi - accused of being a co-conspirator in the 9/11 attacks on the United States - was being subjected to treatment that is banned under international law.

"His torture and ill-treatment are reported to continue," a statement from the UN human rights office said, without giving details of the source of Melzer's information.

"In addition to the long-term effects of past torture, noise and vibrations are reportedly still being used against him, resulting in constant sleep deprivation and related physical and mental disorders, for which he allegedly does not receive adequate medical attention," it said.

Major Ben Sakrisson, a Pentagon spokesman, said the allegation was not true.

"These claims have been investigated on multiple occasions in the past and no credible evidence has been found to substantiate his claims," he said.

The prison, which was opened by former President George W Bush to hold terrorism suspects captured overseas after the 11 September 2001 attacks has come to symbolise harsh detention practices that opened the United States to accusations of torture.

His successor Barack Obama ended the use of "enhanced interrogation techniques" via executive order in January 2009, and reduced the inmate population to 41, but fell short of fulfilling his promise to close the jail.

President Donald Trump asked Congress earlier this year for funds to upgrade the jail, having said during his electoral campaign that he wanted to "load it up with some bad dudes".

Citing a 2014 Senate investigation, the UN statement said al-Baluchi reportedly suffered relentless torture for more than three years in CIA "black sites" before being moved to Guantanamo, where he has been in a severely restricted-access facility for more than a decade.

Al-Baluchi, a Kuwaiti-born Pakistani citizen also known as Abdul Aziz Ali, is the nephew and alleged co-conspirator of Khalid Sheikh Mohammed, the accused mastermind of the 9/11 attacks.

Melzer said the ban on torture and ill-treatment was one of the most fundamental norms of international law and could not be justified in any circumstances.

He called for the prosecution of US officials who may have carried out torture.