Berlin (AFP) - US President Barack Obama arrived in Germany on Wednesday on the final leg of a European tour aimed at reassuring key allies about transatlantic ties under his successor Donald Trump.
Obama touched down in Berlin for a visit due to last until Friday, during which he will hold talks with German Chancellor Angela Merkel as well as the leaders of Britain, France, Italy and Spain.
The outgoing US president arrived from Athens where he had delivered a sweeping speech warning of threats to modern democracy, acknowledging that globalisation had fuelled a "sense of injustice" and needed a "course correction" to address growing inequality.
"When we see people, global elites, wealthy corporations seemingly living by a different set of rules, avoiding taxes, manipulating loopholes... this feeds a profound sense of injustice," he said.
But Obama also offered a ringing defence of liberal democracy, saying: "I firmly believe that the best hope for human progress remains open markets, combined with democracy and human rights."
Trump has been a critic of global free trade agreements and welcomed Britain's shock vote in June to leave the European Union, which was fuelled by a populist campaign harnessing anger over immigration and a perceived loss of power to bureaucrats in Brussels.
But Obama argued that "when people have opportunity and they feel confidence in the future, they are less likely to turn on each other and less likely to appeal to some of the darker forces that exist in all our societies, those that can tear us apart".
In a joint article to coincide with his arrival in Germany, Obama and Merkel voiced support for the controversial Transatlantic Trade and Investment Partnership, making a strong case for trade in stark contrast to Trump's protectionist stance.
"There will be no return to a world before globalisation," they argued in business magazine Wirtschaftswoche.
"We owe it to our companies and our citizens, indeed to the entire world community, to broaden and deepen our cooperation."
- 'My closest partner' -
As Europe desperately seeks clues to future US policy, Merkel, leader of the continent's biggest economy, is being widely touted as the new standard bearer of liberal democracy since the shock election of brash populist and political novice Trump.
Obama has described Merkel as "probably... my closest international partner these last eight years."
European governments, especially eastern countries close 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.
Obama has been at pains to stress that Europe -- and NATO -- would remain the cornerstone of US foreign policy.
The US-led NATO grouping is "absolutely vital" to US interests and a strong, unified Europe was good for America and the world, the president said in comments aimed at calming old partners' fears.
"We know what happens when Europeans start dividing themselves up... the 20th century was a bloodbath," he said pointedly on Tuesday.
- Greece's 'extraordinary compassion' -
Obama was generally welcomed in Greece, though his visit was also met with anarchist-led street protests denouncing US "imperialism", with police firing tear gas Tuesday to push back 2,500 demonstrators trying to reach the city centre.
Elsewhere, Athenians young and old waited patiently in line to catch a glimpse of the leader on his last foreign trip as president, which will wrap up with a stop in Peru after Germany.
"It's fantastic to be here," said 17-year-old pupil Anais Karayanis. "He has plenty of things to teach us, advice to give. I would have come to see Trump as well, but only out of pure curiosity because I don't support him."
Betty Kazakopoulos, a PR consultant in her 60s, said Obama was "a man I admire. Perhaps the last of the great American leaders."
During his visit to the cradle of democracy, Obama has also touched on issues that have shaken Greek society -- a dramatic influx of migrants fleeing war and poverty and a crippling financial crisis.
He lauded Greek islanders' "extraordinary compassion" for the hundreds of thousands of people who have landed on their shores since the start of Europe's worst migrant crisis since World War II.
And he pledged support for its economy, as Greek leaders seek a fresh US pledge to help alleviate the country's enormous public debt, a measure actively sought by the International Monetary Fund but opposed by leading European lender Germany.