President Barack Obama has issued a warning against "crude nationalism" in the wake of Donald Trump's victory, saying the New York billionaire had tapped into a "troubling" strain of rhetoric playing on Americans' fears of globalisation to win the presidency.
Speaking in Athens, Obama on Tuesday said he recognised an "anger and fear in the American population" over threats of mechanisation and globalisation, but that Republican officials did not use facts when making their case about the US economy.
"You've seen some of the rhetoric among Republican elected officials and activists. Some of it is pretty troubling and not necessarily connected to facts, but being used effectively to mobilise people," Obama said at a news conference alongside Greek Prime Minister Alexis Tsipras.
"And obviously, 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."
Obama said countries across Europe, as well as the US, were confronting populist movements based on a fear of intruding global forces, arguing people "are less certain of their national identities or their place in the world".
He said leaders should heed lessons from results in the US and in Britain, which in June voted to exit the European Union.
"It starts looking different and disorienting. And there is no doubt that has produced populist movements, both from the left and the right," Obama said.
"That sometimes gets wrapped up in issues of ethnic identity or religious identity or cultural identity. And that can be a volatile mix."
The outgoing President said Americans must guard against those trends during Trump's presidency, and insisted he, too, would speak out against divisive language even after he leaves office.
Obama is on a week-long, three-stop foreign swing that has taken new urgency following Trump's election.
Obama is the main US president to visit Greece in 17 years, and he concentrated eagerly on the obligation circumstance and the convergence of outcasts escaping the Syrian common war.