US President Barack Obama heads to Europe this week, posiblky his last European visit, that would take him to Poland and Spain where he would attend the NATO summit and hold meetings with top European leaders follwoing Britain's exit from the EU. The situation in Afghanistan, the war against Islamic State terror group after attacks by it in the last month, are likely to dominate the proceedings in addition to post-Brexit European Union and Ukraine, senior administration officials told reporters on the eve of Obama's departure for Europe. "This trip comes at an important time," said Ben Rhodes, Deputy National Security Advisor. "Certainly NATO as the foundation of transatlantic security and the cornerstone of global security, but also our ability to engage with European allies in the context of the aftermath of Brexit, some of the tensions with Russia over the last several years, and the broader concerns about the counter-ISIL effort and the refugee situation," he said. "So many different pressing issues that will be on the agenda at Warsaw and throughout the President's time in Europe," Rhodes said. The US-EU meeting tomorrow, he said, will be a very timely opportunity to discuss the aftermath of the Brexit vote and their continued, very strong support for the European project, which has been at the center of so much security and prosperity for Europe and the US and the world. "They'll review the circumstances in the aftermath of Brexit. They'll also be able to discuss a range of issues we're cooperating with the Europeans. That would include terrorism, migration, economic issues, Russia," he said. In addition to attending the NATO Summit at Warsaw in Poland, Obama would also meet the Ukrainian president along with leaders of the UK, Germany, France, and Italy. "(This is) a format that he's worked with on many issues, but in particular on Ukraine, it's an important opportunity to reaffirm our support for Ukraine's sovereignty and territorial integrity, to stress the urgency of moving forward with the implementation of the Minsk agreements, and expressing our continued determination to maintain sanctions on Russia should they not follow through on those commitments," Rhodes said. From Poland, Obama would travel to Spain, which is the one major European country that he has not visited so far. Doug Lute, US Permanent Representative to NATO said after the Warsaw summit, the command and control of the ballistic missile defense system will pass from the US to NATO. "And of course, the President, in being able to meet with the European leaders and the EU leaders and certainly he'll be seeing Prime Minister David Cameron as well can get a sense from them over how they are thinking about the discussions and negotiations that they will have surrounding the British decision to exit the European Union," he said. "It's possible that this is the President's final stop in Europe, although there may be additional changes. It is certainly his last NATO summit," he added.