REUTERS

Speaking with CBS This Morning co-host Charlie Rose in Germany before meeting with European heads of state, Obama was asked if he believes Russia's President Vladimir Putin is aiming to divide Europe. Obama said that Putin has not always been keen to the idea of European unity.

"Mr. Putin has generally viewed NATO, EU, trans-Atlantic unity, as a threat to Russian power," Obama said.

"Now, I think he's mistaken about that. I've indicated to him that, in fact, a strong, unified Europe working with a strong, outward-looking Russia – that's the right recipe. So far, he has not been entirely persuaded."

Read alsoU.S. lawmakers seeking to allocate $3.4 bln to deter RussiaObama also said he believes the ongoing migrant and refugee crisis is not just a European problem, but a U.S. problem as well.

He expressed concern about how the conversation surrounding the crisis is impacting European politics.

"What I've said to them is that this is not just a European problem. This is our problem too," Obama said.

Read alsoEU aims for joint European coast guard by summer -- Reuters"But more importantly, more strategically, is the strain it's putting on Europe's politics, the way that it advances far-right nationalism, the degree to which it is encouraging a break up of European unity, that in some cases is being exploited by somebody like Mr. Putin."