US President Barack Obama said he will strive during his last international tour as head of state to reassure US allies of President-elect Donald Trump's interest in maintaining his country's core strategic relationships.Hours before leaving on a trip that will take him to Greece, Germany and Peru, the president met reporters on Monday for the first time since Trump's surprise victory over Democrat Hillary Clinton in the November 8 election, Efe news reported.The Republican made controversial comments about foreign policy on the campaign trail, calling NATO "obsolete" and criticizing Washington's partners in the Atlantic Alliance for not spending enough on the military.Asked at the press conference what he will tell world leaders about Trump's approach to foreign policy, Obama referred to the discussion he had with the president-elect last Thursday at the White House."In my conversation with the president-elect he expressed a great interest in maintaining our core strategic relationships, and so one of the messages I will be able to deliver is his commitment to NATO and the Trans-Atlantic Alliance," the outgoing president said."I think that's one of the most important functions I can serve at this stage during this trip is to let them know that there is no weakening of resolve when it comes to America's commitment to maintaining a strong and robust NATO relationship and a recognition that those alliances aren't just good for Europe. They are good for the United States and they are vital for the world," Obama said.Most observers both in the US and abroad were confident that former Secretary of State Clinton would win the presidential contest"Look, we certainly expect that the election will be the primary topic on people's minds everywhere we go," Deputy National Security Adviser Ben Rhodes said in a briefing for journalists ahead of the president's foreign trip.