"I've sought a constructive relationship with Russia," Obama said in a joint news conference with German Chancellor Angela Merkel. "But what I have also been is realistic in recognizing that there is some significant differences in how Russia views the world and how we view the world."
"My hope is that the president-elect coming in takes a similarly constructive approach, finding areas where we can cooperate with Russia where our values and interest align," Obama said. "But that the president-elect also is willing to stand up to Russia where they are deviating from our values and international norms."
The president said he doesn't expect Trump to follow the exact approach as the Obama administration, but hopes Trump considers what the short- and long-term problems that a deal with Russian President Vladimir Putin could bring.
Trump shouldn't "simply take a realpolitik approach and suggest that if we just cut some deals with Russia, even if it hurts people or even if it violates international norms or even if it leaves smaller countries vulnerable or creates long-term problems in regions like Syria, that we just do whatever's convenient at the time," Obama said.
He added that he is encouraged by Trump's commitment to the U.S. partnerships with other countries.
Obama also spoke on the demands of the U.S. presidency.
"If you're not serious about the job, then you probably won't be here very long because it will expose problems the president-elect is going to see fairly quickly ... that the demands and responsibility of a U.S. president are not ones you can treat casually," Obama said.
Obama, on what's probably his farewell overseas trip as president, met with Merkel in Berlin to discuss trans-Atlantic cooperation on a wide range of issues.
The president discussed with Merkel the importance of maintaining sanctions against Russia until it fully implements the Minsk accord that's designed to encourage Russia to reduce the conflict in Ukraine.
Obama also said it's important that the Transatlantic Trade and Investment Partnership negotiations and channels of communication remain.
"The negotiations on agreements like T-TIP have been challenging, and obviously at a moment when there is concerns about globalization," Obama said during a press conference.
Merkel said she will do everything to work well with Trump.
"Alliances are part of our destiny as a nation, part of our future as a nation, and this is what guides me in my policy and my government as a whole," Merkel said.
Merkel is expected to run for a fourth term .