Europe is starting to get twitchy about the "bromance" between Republican presidential candidate Donald Trump and Vladimir Putin, especially after U.S. politician heaped more praise on the Russian president Wednesday.

Speaking at the televised Commander-in-Chief Forum hosted by NBC News on Wednesday, Trump said the Putin, who he has praised several times in the past, was a "far more" capable leader that U.S. President Barack Obama. He also defended Putin's leadership style, support for the Syrian dictator Bashar al Assad and the annexation of Crimea from Ukraine.

"The man has very strong control over a country," Trump said of Putin. "It's a very different system and I don't happen to like the system, but certainly, in that system, he's been a leader, far more than our president has been a leader."

The comments caused a stir both in the U.S. and Europe. Russia and its leader are still viewed warily in both regions despite an awkward military alliance trying to combat the militant group calling itself Islamic State in Syria and Iraq.

Putin's decision in 2014 to annex Crimea from Ukraine and its role in a pro-Russian uprising in Ukraine prompted the U.S. and Europe to impose economic sanctions on Russia which are still in place. NATO has also deployed troops to the Baltic region and Eastern Europe to deter Russia from further military provocations (which have included intrusions into European waters and airspace) or, in the unlikely and worst case scenario, invasions.

Europe's media reacted on Thursday to Trump's warm comments about Putin with a mixture of skepticism, disbelief and nervousness over where the relationship could leave Europe should Trump come to power.

Most U.K. newpapers carried coverage of Trump's praise of Putin with the country's left-leaning Guardian newspaper saying it was continuation of the "so-called bromance" that has blossomed between the men.

"Trump again lavished praise on Vladimir Putin, pledging a new era of US-Russian cooperation – something both Obama and George Bush attempted and failed to achieve after U.S. and Russian interests diverged," the Guardian's Spencer Ackerman wrote.

"Despite months of Russian military demonstration in Syria that Vladimir Putin's objective is to suppress Bashar al-Assad's domestic resistance, Trump claimed that Russia wished to defeat Isis "as badly as we do". Putin might be a dictator – Trump waved away moderator Matt Lauer on this point – but he had "very strong control."

The BBC noted on its online coverage of Trump's remarks at the forum that his praise of Putin, in contrast with Obama's performance in office, "came on the same day the chief of the Pentagon accused Russia of sowing the seeds of global instability."

The BBC's Washington correspondent Anthony Zurcher said Trump had also "found new and interesting ways to show his tenuous command of policy details and shower questionable praise on a U.S. rival (Putin)."

Despite NBC's moderator running through a list of Putin's more controversial actions ("He's also a guy who annexed Crimea, invaded Ukraine, supports Assad in Syria, supports Iran, is trying to undermine our influence in key regions of the world, and according to our intelligence community, probably is the main suspect for the hacking of the DNC computers") Trump responded that President Obama was just as bad.

"Do you want me to start naming some of the things that President Obama does at the same time?" Trump asked.

Trump's comments were not lost on continental Europe either with most large European news outlets remarking on Trump's continued approval of Putin. German daily Der Spiegel led with Trump's "praise for Putin" and said the U.S. businessman-turned-presidential hopeful had "emphasized once again his closeness to Russia" during the forum.

Meanwhile Sueddeutsche Zeitung reported on Trump's "controversial" remarks about Putin and said Trump showed no signs of disassociating himself from the Russian leader, an observation also made in the French press.

-NBC's Benjy Sarlin and Alex Seitz-Wald contributed reporting to this story.

Follow CNBC International on Twitter and Facebook.

More From CNBC

• Top News and Analysis
  

• Latest News Video
  

• Personal Finance