WASHINGTON — President Barack Obama is slated to embark on a five-day, two-country mission to buck up a beleaguered Europe and brush back an aggressive Moscow on what is expected to be his last presidential visit to the continent.

Obama is due to attend a summit of NATO allies in Warsaw, before moving on to Seville and Madrid for his first presidential visit to Spain. In both corners of the continent, he’ll be surrounded by leaders still reeling from Britain’s decision to pull out of the European Union and sorting through uncertainty about the future of the decades-old experiment in international cooperation.

The White House says Obama will arrive with words of reassurance that the departure — whenever it occurs — won’t disrupt the decades-old trans-Atlantic ties that bind. He’ll emphasize that Britain’s exit, which does not affect its membership in NATO, only makes the 28-member military alliance more essential and its cooperation with the European Union more important. And amid leaders’ anxiety about whether his possible successor, Republican Donald Trump, would retrench from Europe, Obama will make case for stronger alliances and the benefits of globalization.

Obama plans to emphasize America’s “continued, very strong support for the European project which has been at the center of so much security and prosperity” around the world, said Ben Rhodes, deputy national security adviser.

The president’s arrival early Friday will be his first chance to deliver that message in person, both to the European leaders tasked with smoothly navigating the tricky divorce and British Prime Minister David Cameron, whom Obama personally tried but failed to save from the wave of anti-European sentiment that fueled the vote.