The defense chief of Germany's Bundeswehr, General Carsten Breuer, and the United Kingdom's chief of the defence staff, Air Chief Marshal Sir Richard Knighton, have jointly stated the case for rearming, amid the threat posed by Russia.

The top military officials penned a joint letter, published in The Guardian and German newspaper Welt, in which they said there was a "moral" case to be made for rearming.

What the German and UK military leaders said

Breuer and Knighton said that they were speaking "not merely as the military leaders of two of Europe's largest military spenders, but as voices for a Europe that must now confront uncomfortable truths about its security."

The pair said that Russia's military posture had "shifted decisively westward" and that it was rearming and learning lessons from its invasion of Ukraine while "reorganizing in ways that could heighten the risk of conflict with NATO countries."

The military leaders said Russia's military buildup "combined with its willingness to wage war on our continent, as painfully evidenced in Ukraine, represents an increased risk that demands our collective attention."

Russia 'may be emboldened' by any perception of a weak Europe

The leaders warned that should Russia perceive weakness or disunity within Europe "it may be emboldened to extend its aggression beyond Ukraine."

To this end, the letter stated that "Military readiness must mean a strong defense industry" with the pair highlighting the munitions factories being built in the UK and the stationing of a German combat brigade on NATO's eastern flank, while also mentioning Berlin's efforts to make "essentially unrestricted funding available for defense."

The German government is spending considerably more on defense as it seeks to modernize and strengthen the Bundeswehr — which has seen decades of cutbacks.

Russia's full-scale invasion of Ukraine in February 2022 triggered an about-turn in Germany's security policy that had previously been premised on military restraint.

'Rearmament is not warmongering' defense chiefs say

Their letter added: "There is a moral dimension to this endeavor. Rearmament is not warmongering; it is the responsible action of nations determined to protect their people and preserve peace. Strength deters aggression. Weakness invites it."

Breuer and Knighton concluded by saying that "a whole-of-society" approach was necessary and that defense could not be shouldered by those in uniform alone.

"Whole-of-society defense requires resilient infrastructure, research and development in hi-tech from the private sector, and national institutions prepared to function under increasing threats," the military chiefs said.

"When Europe acts together, we are a formidable force. And we act together, we are not Great Britain and Germany alone."

The military chiefs' warning follows the conclusion of the annual Munich Security Conference, which saw world leaders meet to discuss Europe's defense and the war in Ukraine.

Edited by: Alex Berry