Obama: 'Guard Against a Rise in a Crude Sort of Nationalism or Ethnic Identity or Tribalism'

"Sometimes people just feel as if we want to try something to see if we can shake things up," Obama continued. "And that, I suspect, was a significant phenomenon. I do believe, separate and apart from any particular election or movement, that we are going to have to guard against a rise in a crude sort of nationalism or ethnic identity or tribalism that is built around an us and a them. And I will never apologize for saying that the future of humanity and the future of the world is going to be defined by what we have in common as opposed to those things that separate us and ultimately lead us into conflict."

"Take Europe. We know what happens when Europeans start dividing themselves up and emphasizing their differences and seeing a competition between various countries in a zero sum way. The 20th Century was a bloodbath, and for all the frustrations and failures of the project to unify Europe, the last five decades have been periods of unprecedented peace, growth, and prosperity in Europe. And the United States, we know what happens when we start dividing ourselves along lines of race or religion or ethnicity."

Obama called division "dangerous, not just for the minority groups that are subjected to that kind of discrimination or, in some cases in the past violence, but because we then don't realize our potential as a country when we're preventing blacks or Latinos or Asians or gays or women from fully participating in the project of building American life."

"So my vision's right on that issue. And it may not always win the day in the short term in any particular political circumstance," he added. "But I'm confident it will win the day over the long term because societies in which we are able to unify ourselves around values and ideals and character and how we treat each other and cooperation and innovation, ultimately are gonna be more successful than societies that don't."

Tsipras said he knows "very little of Donald Trump -- I got to know his aggressive manner and the manner in which he defended some unconventional points of view during the election period."

"Those who believe that if someone who would want to radically change the foreign policy of a country such as the United States, which is very difficult, and often although some of us in here who may fear that this may happen, what we should be doing is build bridges, not walls," the prime minister said.