On Monday, Obama tried to reassure worried allies, stressing that dismantling or unravelling such agreements was not easy.
US President Barack Obama will arrive in Athens on Tuesday, the first stop on a final foreign trip that will aim to reassure worried Europeans following Donald Trump's surprise presidential election victory.
The 44th president of the United States had likely imagined his farewell visit to Europe -- coming after eight years in power -- in different circumstances.
But Trump's defeat of Hillary Clinton last week will be on everybody's minds as the future of several key global deals -- on issues such as Iran's nuclear programme and the environment -- looks uncertain.
During a press conference in Washington on Monday, Obama tried to reassure worried allies, stressing that dismantling or unravelling such agreements was not easy.
After travelling to Greece, Obama will head to Germany to meet Chancellor Angela Merkel, French President Francois Hollande and British and Italian prime ministers Theresa May and Matteo Renzi.
He will conclude his trip with a stop in Peru for a summit of the Asia-Pacific Economic Cooperation forum (APEC). Among the leaders he is expected to meet there is President Xi Jinping of China.
Obama on Wednesday will visit the Parthenon in Athens, then deliver a speech -- sure to have considerable resonance, given the recent US elections -- on the challenges of globalisation.
The question of Greek debt, which is choking the economy, and the hundreds of thousands of migrants who have arrived in Greece fleeing conflict in the Middle East will be the focus of talks during Obama's first visit to the country.
Shortly after his arrival in Athens, where thousands of police officers have been deployed amid tight security in the capital, Obama will hold a joint press conference with Greek Prime Minister Alexis Tsipras.
"It's a symbolic and rare visit that recognises Greek efforts to manage its debt and to stabilise the country," government spokesman Dimitris Tzanakopoulos said.
According to Greek Finance Minister Euclide Tsakalotos, the election of Trump could strengthen Greece's position against its creditors.
"We live in an uncertain world and this could help Greece. Because the European Union and the eurozone must show that they can resolve their problems among themselves," he told German newspaper TAZ.
Subjected to tough austerity measures, Greece is struggling to emerge from recession despite a recent upturn in its finances.
"In order for the reforms to be sustainable, people need hope," Obama said in an interview with Greek daily Kathimerini.
He promised to continue urging Greece's creditors to "take the necessary measures, particularly in regard to debt relief, so it can return to robust economic growth".
Obama will also highlight "the compassion and the generosity" that the Greek people have shown to refugees and migrants landing on their shores.
Rights group Amnesty International called on him to take advantage of the visit "to draw attention to the appalling conditions suffered by the tens of thousands of refugees trapped in Greece", and to demand wealthy nations assume responsibility.
Civil servants, communists, far-left groups and anarchists all plan to hold demonstrations as Obama swings through the Greek capital.