Republican Donald Trump has repeated calls for the return of waterboarding against Islamic State militants, saying, he likes it a lot.
His comments at a rally in Ohio came hours after suicide bombers killed 41 people at an airport in Istanbul.
"You have to fight fire with fire," said the Republicans' likely nominee, after referring to IS beheadings.
Water-boarding, described by President Barack Obama as torture, was banned by the US in 2006.
The Turkish authorities believe the so-called Islamic State was behind the attacks at Ataturk International Airport on Tuesday.