A day after President Trump proclaimed the torture of enemies and terrorists "absolutely" works, Sen. John McCain offered a sharp rebuke, telling reporters in Philadelphia that such tactics run counter to the country's principles.

"Torture takes away the most important aspect of the United States of America — we are a moral nation, we are not like other countries, we don't torture people," the Arizona Republican said. "It's not only the issue of torture it's also the issue of what kind of nation we are."

McCain, who was held as a prisoner of war and tortured in Vietnam, spoke out at the Loews hotel, where Congressional Republicans are holding their annual retreat.

His comments came the morning after Trump told ABC News that he supports such tactics and that his administration would reconsider them as part of a review of the nation's war against terrorism. Trump would also not rule out re-opening so-called "black site" prisons run outside the country by the CIA.

McCain did not support Trump for president and said he will not react to every issue on which he and the President disagree -- but that he will speak out on certain topics.

"When he brings up this issue of torture again, I have to speak up -- I have to speak up, I have to -- I have no choice on that," McCain said, later adding, "Because of legislation, because of my own personal experience, because of everything that I've seen."

McCain said that prominent generals and senior military officials "will tell you: It. Does. Not. Work."

McCain also said U.S. law is clear and leaves no wiggle room for re-opening the idea of torturing detainees, though Trump, in his ABC interview, said the country must "fight fire with fire" when confronting extremists.