US President Barack Obama has called the Nato alliance "absolutely vital" to US interests, as he arrived in Europe to reassure nervous allies concerned by Mr Donald Trump's election victory.
Speaking in Athens yesterday, Mr Obama stressed that a strong Europe was "good for the world and the US", after Mr Trump appeared to downplay the importance of historic transatlantic ties.
On Monday, he warned that the incoming President faces a reality check if he tries to enact some of his more controversial campaign promises.
"Do I have concerns? Absolutely. Of course, I have concerns. He and I differ on a whole bunch of issues. But the federal government and our democracy is not a speedboat - it's an ocean liner," he said.
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