Obama in Europe to reassure allies

Obama on Trump

-Trump is pragmatic, not 'ideological'

-Says Iran, climate deals would be difficult to unravel under Trump

-Urges Trump to reach out to non-supporters saying 'gestures matter'

The Nato alliance is "absolutely vital" to US interests, President Barack Obama said yesterday, as he flew in to Europe to reassure jittery allies concerned by Donald Trump's shock presidential election win.

Speaking in Athens on the first leg of his last foreign trip as leader, Obama stressed that a strong Europe was "good for the world and the US", after Trump appeared to downplay the importance of historic transatlantic ties.

Europeans, especially in eastern countries closest to Russia's orbit, have been shaken after Trump appeared to call into question Washington's near 70-year security guarantee by saying he would only help Nato allies if they paid their way.

But Obama stressed that the transatlantic relationship was the "cornerstone of our mutual security as well as prosperity" and that was the case regardless of who was sitting in the Oval Office.

"Across Democratic and Republican administrations there is a recognition that the Nato alliance is absolutely vital," he said.

As Obama touched down in Athens, Nato head Jens Stoltenberg said he was confident Trump would live up to US commitments to the alliance.

Obama travels to Germany today, where he will speak with close ally Chancellor Angela Merkel as well as the French and British leaders.

He concludes his trip with a stop in Peru for a summit of the Asia-Pacific Economic Cooperation forum (APEC) where he is expected to meet Chinese President Xi Jinping.

Speaking to reporters on the eve of the trip, Obama cautioned his brash successor that he faces a reality check if he tries to enact some of his __more controversial campaign promises.

Trump's election win last week over Hillary Clinton has been met with euphoria among his supporters, but also with a wave of protests across the nation that are unusual for the world's leading democracy.

Obama said that deporting millions of immigrants, tearing up mutual defense treaties with Nato and Japan, and unraveling global deals on Iran's nuclear program and the environment were not as simple as delivering tub-thumping rhetoric.

"Regardless of what experience or assumptions he brought to the office, this office has a way of waking you up," Obama said.

Obama said that during a meeting with Trump at the White House last week, he had told the president-elect that his actions can move markets, tanks and public sentiment.

"I emphasised to him that, look, in an election like this that was so hotly contested and so divided, gestures matter," Obama said. "It's really important to try to send some signals of unity".

"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."

Amid dire predictions about the end of the republic and the global order, Obama said that Trump's inexperience in politics and lack of intellectual baggage could be an asset. "I don't think he is ideological. I think ultimately he is pragmatic in that way.  And that can serve him well as long as he's got good people around him and he has a clear sense of direction," he continued.