Britain's defense secretary says his country expects President-elect Donald Trump to "stand up" to Vladimir Putin once he's in the White House, despite the Manhattan billionaire's praise for the Russian president on the campaign trail.

Sir Michael Fallon warned Monday that Britain does not plan to be singled out on the international stage by its hardline position toward Putin. He encouraged Trump not to treat the Kremlin as an "equal partner."

Putin was one of the first foreign leaders to congratulate Trump on his unexpected victory — with a telegram, no less — and the two men have signaled that a new relationship based on "mutual respect" is on the horizon between the U.S. and Russia.

But despite Trump's history flattering comments about Putin, Fallon isn't convinced he will actually cozy up to Russia once he is sworn in as president in January.

"I think you have to distinguish between the campaign rhetoric of President-elect Trump and what he does in practice," the British leader said. "[I]n practice, every American administration has always stood up to Russia. We’re not suggesting you shouldn’t talk to Russia, but what you can’t do is treat Russia as business as usual, as any kind of equal partner."

"Russia is clearly breaking the international rules by what it did in Crimea and Ukraine and that can never be forgotten," he added.

Fallon also raised concerns about NATO, given Trump's criticism of the alliance on the campaign trail. Earlier this month, though, Jens Stoltenberg, the secretary general of NATO, said he is "absolutely confident" Trump will maintain the United States' role in the group.

Fallon, for his part, believes Putin "is testing the alliance and we have to respond":

We have to make clear that NATO is a defensive alliance but ultimately it is prepared to come to the defense of those members who feel very vulnerable, particularly on the eastern flank – countries like the three Baltic states and Poland in particular. For members of NATO itself, it is extremely important now that the alliance pulls itself together, NATO members increase their defense spending – Poland and Britain actually meet the 2 percent commitment – and that we do reassure those members that feel extremely vulnerable.

The defense secretary also made clear that he believes Russia has an obligation to stop the bloody refugee crisis in Syria by wielding its authority over President Bashar al-Assad's regime, saying, "In the end, yes, we can’t stop this civil war; in the end, it does depend on Russia recognizing its responsibilities, bringing the war to an end and, above all, letting humanitarian aid into eastern Aleppo."