Germany and Denmark's political leaders met on Tuesday in a show of unity amid concerns about Russian hybrid warfare in the Baltic Sea and possible US designs on the annexation of Greenland.

Danish Prime Minister Mette Frederiksen and German Chancellor Olaf Scholz addressed the threat posed to European security, most immediately by Russia and China.

What the leaders said

Scholz referred to the most recent damage to undersea cables in the Baltic Sea that many have attributed to Russia and its shadow fleet of sanctions-busting ships.

"Just yesterday, there was another report that another submarine cable had been damaged. This shows the threat posed by the Russian shadow fleet."

The chancellor referred to a recently launched mission by the NATO military alliance to protect subsea infrastructure in the Baltic.

"With NATO Operation 'Baltic Sentry', we will improve the protection of the Baltic Sea and the critical infrastructure on the seabed." It is clear that NATO remains "the guarantor of our common security," Scholz added, arguing that this is why many allies have significantly increased their defense spending in recent years.

The German chancellor did not directly mention US President Donald Trump's renewed interest in making Greenland a part of the United States. However, he appeared to hint at it during the press conference.

"Borders may not be moved by force: To whom it may concern!" he said.

Mette underlined the notion that Europe needed to take responsibility for its own security.

"We need to step up in Europe, we need a stronger and a more resolute Europe standing increasingly in its own right, capable of defending and promoting Europe and the European interests," she said. "It is up to Europe to define the future of our continent. And I think we have to take more responsibility for our own security, strengthening our defense industry."

What's behind the comments?

The pair's comments came after a cable under the Baltic Sea, between Sweden and Latvia was severed in a suspected act of sabotage. Latvia deployed a warship in the immediate aftermath and has claimed the damage was likely caused by "external influence."

A Bulgarian vessel that set sail from Russia days earlier has been seized by Swedish authorities while an investigation takes place.

It was the latest in a series of incidents that have raised fears of Russian sabotage and spying in the strategic region.

Launched earlier this month, the Baltic Sentry operation involves frigates, maritime patrol aircraft and a fleet of naval drones to provide "enhanced surveillance and deterrence" to protect undersea infrastructure.

Mette was visiting Berlin as part of a tour of major European capitals with the continent facing what she called "a more uncertain reality."

On Monday evening, her government announced a roughly 14.6 billion-kroner (nearly $2 billion; €1.92 billion) agreement with parties including the governments of Greenland and the Faeroe Islands to bolster its military presence around Greenland.

The move came after Trump repeated his interest in making Greenland part of the United States. The island, which is largely self-governing under the Danish crown, with defense and foreign affairs provided by Denmark, is believed to hold vast natural resources and is strategically situated for control of the Arctic.

rc/rmt (AFP, AP, dpa, Reuters)