President Barack Obama addressed journalists during a joint news conference with Greek Prime Minister Alexis Tsipras in Athens, Greece on Nov. 15, 2016. Reuters/Yorgos Karahalis/Pool

During a joint press conference with Greece's Prime Minister Alexis Tsipras Tuesday, President Barack Obama presented in stark terms the challenge ahead of Americans following a divisive election. Obama said President-elect Donald Trump was able to tap into a "troubling" set of fears and style of rhetoric to win the White House.

"You've seen some of the rhetoric among Republican elected officials and activists and media. Some of it pretty troubling and not necessarily connected to facts, but being used effectively to mobilize people," Obama said during his visit to Greece. "And obviously President-elect Trump tapped into that particular strain within the Republican Party and then was able to broaden that enough and get enough votes to win the election."

Trump regularly insulted people along his way to the White House and has stoked fears in the left after he named Stephen Bannon, the former Breitbart executive who is a favorite of white nationalists, as chief advisor.

Obama stressed in stark terms that divisive, populist politics could have terrible results. Nationalism in Europe in the 20th century resulted in a "bloodbath," the president said.

"People are less certain of their national identities or their place in the world. It starts looking different and disorienting," Obama said. "And there is no doubt that has produced populist movements, both from the left and the right. That sometimes gets wrapped up in issues of ethnic identity or religious identity or cultural identity. And that can be a volatile mix."

Obama's stop in Greece is the first of a few as he attempts to quell global concerns about Trump winning the election last week. The president is scheduled to make stops in Germany and Peru as well. Before departing on the trip Obama attempted to project confidence about the state of the U.S. and said Trump suggested that he intended to keep its NATO commitments, something the president-elect had claimed he could ignore.