NATO Secretary-General Mark Rutte cautioned the United States and Europe on Wednesday against the perils of unilateralism, stressing that security threats demand a united front rather than isolated efforts.

His remarks come as concerns grow over the future of the transatlantic alliance, following U.S. President Donald Trump’s recent statements questioning America’s commitment to defending NATO allies that fail to meet defense spending targets. European leaders, facing an emboldened Russia, have responded with alarm.

Speaking at the Warsaw School of Economics, Rutte emphasized the necessity for European nations to take greater responsibility for collective security, while also underlining NATO’s irreplaceable role.

"This is not the moment for Europe or North America to act alone," Rutte declared. "The security challenges we face are too vast for any one of us to handle in isolation. There is no substitute for NATO in keeping our regions safe."

In response to shifting geopolitical dynamics, countries such as Germany and the United Kingdom have committed to increasing defense expenditures. Meanwhile, Trump has advocated for NATO members to allocate 5% of their GDP to defense—more than double the current 2% target, a threshold even the U.S. has yet to reach.

Rutte acknowledged the importance of American support but insisted that European allies must also rise to the occasion. "Yes, Europe needs to be reassured that America stands with us. But America, too, must see that its NATO partners are ready to share the burden," he stated.

Looking ahead to NATO’s June summit in The Hague, Rutte framed the gathering as a pivotal moment for the alliance’s future. "This will mark the beginning of a new era for NATO—one that is stronger, fairer, and more formidable," he asserted. "A truly fair NATO requires all members to pull their weight."