Speaking alongside German Chancellor Angela Merkel in Berlin, Obama said he hopes Trump is “willing to stand up to Russia where they are deviating from our values and our international norms.”

Obama acknowledged he didn't expect Trump to follow "exactly our blueprint" but advised him to pursue a foreign policy that defends democratic principles worldwide.

“My hope is he does not simply take a realpolitik approach and suggest that if we just cut some deals with Russia, even if it hurts people ... that we just do whatever's convenient at the time,” the president added.

Trump has sparked concerns among leaders at home and abroad by making overtures to Russia during his presidential campaign.

The Republican leader praised Russian President Vladimir Putin as “a leader far more than our president has been.”

During a post-election phone call, both men pledged to mend frayed ties between the U.S. and Russia, according to the Kremlin.

Obama recommended that Trump find ways to work with Russia, but also cautioned him against compromising the U.S. interests in areas like the conflict in Syria and cyberspace.

"I've sought a constructive relationship with Russia," Obama said, citing the Iran nuclear agreement. "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."

The Obama administration has been frustrated by the Kremlin’s support for Syrian President Bashar Assad, arguing it has helped prop up a regime responsible for hundreds of thousands of deaths in the country’s civil war.

The U.S. government has also blamed a series of cyberattacks on Democratic Party organizations on actors tied to the Russian government, saying it was an effort by the Kremlin to influence the outcome of the presidential election.

The president sought to reassure European allies, such as Merkel, that Trump is fully committed to NATO.

Even though Trump suggested the U.S. would pull away from NATO during the campaign, Obama said he’s received assurances from Trump that the transatlantic alliance “is a commitment that does not change.”

Obama's own approach to Russia has been subject to growing criticism. The president pursued a "reset" with the Kremlin early in his administration, but the effort fell apart over the Syrian conflict and Ukraine intervention.

Republicans have accused Obama of not taking Russia's rise seriously enough early on. They point to his 2012 presidential debate with Mitt Romney, when he scoffed at the GOP nominee's suggestion that Moscow posed the greatest geopolitical threat to Washington.