In what is likely to be his last visit to Europe as president, Barack Obama has arrived in the Polish capital Warsaw to attend a two-day Nato summit, where his discussions are expected to be dominated by the aftermath of Brexit.

The White House said Obama will assure Britain that its vote to leave the European Union will not affect the decades-old trans-Atlantic relations. He will be meeting the leaders of the 28-member nations to discuss how they plan to negotiate Britain's exit.

Obama had ardently campaigned against the EU referendum and this trip will see him sit with the presidents of the European Council and the European Commission personally to deliver his message to help Britain navigate its exit smoothly.

Ben Rhodes, Obama's deputy national security adviser, said: "He [Obama] feels like all leaders in Europe and in the United States - including himself – have a responsibility in the face of all these challenges to the trans-Atlantic order that we've built to make the case on behalf of the values that the Unites States and Europe have stood for and the benefits to our countries," the Associated Press reported.

Apart from Brexit, Obama will be discussing the Syrian refugee crisis, alleged Russian aggression and Ukraine. He is expected to urge the European partners to stand firm over Russia's seizure of the Crimea and its support for the Russian-speaking rebels in eastern Ukraine, Reuters reported.

Besides, he will meet Ukraine President Petro Poroshenko on Saturday (9 July) to review the status of the stalled 2015 Minsk peace deal which was intended to ease the Russia-Ukraine conflict.

"Russia is trying to engage in a battle of ideas," Rhodes told reporters abroad Air Force One. He said Moscow feels threatened by countries like Ukraine as they want to maintain closer ties with Europe.

Obama is also slated to visit Seville and Madrid - his first presidential trip to Spain - on Saturday (9 July).

Obama NATO troops
Apart from Brexit, Barack Obama will be discussing the Syrian refugee crisis NICHOLAS KAMM/AFP/Getty Images