From Gregor Stewart Hunter, Ray Wei, and John Yuan Young

Singapore, May 31 (Reuters) - The United States again leveled sharp criticism at its NATO allies during a meeting in Singapore earlier this week, but officials from Western European countries insisted the alliance remains intact.

In a speech during the Shangri-La Dialogue, US Defense Secretary Pete Hegseth praised Asian partners for increasing defense spending and moving closer to Washington at a time of escalating tensions with China.

He said, "When our interests align, we act together with determination and resolve... and when our interests diverge, we adapt pragmatically without drama or moralizing. I think Western Europe might take that into account."

He added, "Europe and NATO have some important decisions to make."

The administration of President Donald Trump has repeatedly accused European governments of not investing enough in their militaries and relying too heavily on American protection, and has urged its allies in Europe and Asia to increase defense spending to 3.5 percent of GDP.

In May, Washington announced plans to withdraw 5,000 troops from Germany, and Trump threatened to withdraw from NATO.

A senior NATO official sought to downplay the significance of the US troop withdrawal, saying it was already planned and that the alliance's cohesion was unaffected.

"In a mature alliance, if one ally, in this case the main contributor, needs to redirect some force elsewhere, it can do so, and the others should cooperate," said Admiral Giuseppe Cavo Dragone, chairman of NATO's Military Committee.

Nils Helmer, Germany's State Secretary for Defense, said Berlin is working to accelerate military investment regardless of future US deployments.

He said, "What we know for sure... is that there will be changes in this area... that's why we are about to take security matters into our own hands."

European ministers also used the forum to reassure Asian partners that NATO still enjoys credibility beyond its immediate neighbors.

French Defense Minister Catherine Vautrin told participants, "Our credibility in Asia also depends on our strength in Europe, and on defending Ukraine against Russian aggression."

Other European defense ministers noted that areas of security operations are becoming increasingly complex.

Norwegian Defense Minister Tore Sandvik said, "The Euro-Atlantic and Indo-Pacific operational areas have become inseparable," and in this regard he pointed to the participation of North Korean forces in battles in Ukraine.

He added, "The United States will be involved in more areas."

But despite all the criticism from the US Department of Defense (the Pentagon), a number of US senators and representatives said they were seeking to reassure European and Asian allies that they had bipartisan support in Congress.

U.S. Senator Tammy Duckworth said, "I've heard the same concern from everyone, not just in the region... In fact, there are NATO allies who are worried about America's commitment to the Indo-Pacific region."

But others remain skeptical about the pace of change in Europe regarding investment in collective security.

“Europe has to learn how to become a major player… there’s no escaping it,” said Pavlo Klimkin, an associate fellow at the Carnegie Endowment for International Peace and a former Ukrainian foreign minister. “But this could be very useful for its partnership with the United States, because the United States would respect such European momentum.”