CIA director John Brennan
CIA director John BrennanReuters

CIA chief John Brennan has indicated that he will quit his job before he carries out the order of the next president to employ "waterboarding," an interrogation technique simulating the sensation of drowning, a practice opponents have claimed constitutes torture.

Brennan's statement is apparently a snub of Republican presidential candidate Donald Trump, who has expressed support for renewing the practice, which was banned in 2009 by current President Barack Obama, along with other "enhanced interrogation techniques."

Brennan's recent pronouncement is a step up from a similar one he made in April, when he claimed in an interview with NBC that he would "not agree to carry out some of these tactics and techniques that I've heard bandied about because this institution needs to endure."

In one of the Republican presidential debates, Donald Trump pledged that he "would bring back waterboarding, [and] a hell of a lot worse than waterboarding."