WASHINGTON - US Republican White House front-runner Donald Trump said on Sunday he would be open to harsh measures to deal with the threat from Islamic State, including going beyond the controversial interrogation tactic known as waterboarding.In an interview on ABC's "This Week" program, Trump discussed reviving the tactic and implementing other interrogation techniques, pointing to the recent beheadings of Christians in the Middle East as evidence of the need for stronger interrogation methods for suspected operatives of extremist groups."We're like living in medieval times," he said. "If I have to do it and if it's up to me, I would absolutely bring back waterboardng. And if it's going to be tougher than waterboarding, I would bring that back, too."When pressed by interviewer George Stephanopoulos if that meant the United States employing similar methods of beheading captors, Trump responded: "We're going to do things beyond waterboarding," adding, "Perhaps, if that happens to come."