John McCain, the US senator subjected to brutal treatment as a prisoner in North Vietnam, questioned Tuesday the nomination of a CIA official once involved in torture to lead the spy agency.
McCain said Gina Haspel, currently the deputy director of the Central Intelligence Agency, must pledge "without reservation" to oppose the use of torture if she is to be approved as director.
"The torture of detainees in US custody during the last decade was one of the darkest chapters in American history," McCain said in a statement.
"Ms. Haspel needs to explain the nature and extent of her involvement in the CIA's interrogation program during the confirmation process."
President Donald Trump on Tuesday nominated Haspel, 61, to replace Mike Pompeo, who has been named to take over the State Department after the top US diplomat, Rex Tillerson, was fired.
Haspel, who has had a long career in the CIA's clandestine service, ran the agency's "black box" interrogation cell in Thailand after the September 11 attacks.
Two high-profile al-Qaeda detainees, Abu Zubaydah and Abd al-Rahim al-Nashiri, were subjected to waterboarding and other torture methods while they were held in the secret prison.
McCain, a navy pilot, was shot down over North Vietnam in 1967. Taken prisoner, his severe injuries weren't treated and he was repeatedly bound and beaten.
Since then he has steadfastly opposed the use of torture by the US government.
"In the aftermath of the September 11th attacks, our government squandered precious moral authority in a futile effort to produce intelligence by means of torture," McCain said.
"We are still dealing with the consequences of that desperately misguided decision."
"Current US law is clear in banning enhanced interrogation techniques. Any nominee for director of the CIA must pledge without reservation to uphold this prohibition," he said.