President Obama arrived in the Greek capital Tuesday morning, beginning a week-long foreign trip in which he will serve as an unlikely emissary of President-elect Donald Trump.

Obama said he would seek to reassure anxious European allies that the United States will continue its bipartisan commitment to the North Atlantic alliance — regardless of Trump's campaign rhetoric that often suggested otherwise.

"In my conversation with the president-elect, he expressed a great interest in maintaining our core strategic relationships," Obama said in a news conference before departing Washington Monday.

"And so one of the messages I will be able to deliver is his commitment to NATO and the Transatlantic Alliance. I think that's one of the most important functions I can serve at this stage, during this trip, is to let them know that there is no weakening of resolve when it comes to America's commitment to maintaining a strong and robust NATO relationship, and a recognition that those alliances aren’t just good for Europe, they're good for the United States, and they're vital for the world."

During the campaign, Trump distressed NATO allies by suggesting that the United States could pare back its commitment to the 67-year-old treaty organization. Trump complained that European allies weren't paying their fair share on defense (Greece is one of five who do) and suggested that NATO is still stuck in a Cold War mentality unsuited to the modern-day threat of terrorism.

Greece is the first stop in what's scheduled to be Obama's farewell foreign tour. He'll also visit Germany on Wednesday, where he'll meet with Chancellor Angela Merkel and the heads of the United Kingdom, France, Italy and Spain. From there he'll pivot to Asia, meeting with Pacific Rim powers at the Asia Pacific Economic Cooperation summit in Peru.

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