In a foreign policy address in Brussels, Mike Pompeo told diplomats: "In the finest traditions of our great democracy, we are rallying the noble nations to build a new liberal order that prevents war and achieves greater prosperity.
"Under President Trump, we are not abandoning international leadership or our friends in the international system.”
Despite Mr Trump’s “America first” mantra, Mr Pompeo rejected suggestions the president was acting without consideration for other nations.
"Even our European friends sometimes say we're not acting in the free world's interest,” he said. “This is just plain wrong.
"We are acting to preserve, protect, and advance an open, just, transparent and free world of sovereign states.
“This project will require actual, not pretend, restoration of the liberal order among nations. It will require an assertive America and leadership from not only my country, but of democracies around the world."
Mr Pompeo said the US was pushing the World Bank and the International Monetary Fund to reduce funding to countries such as China, who he said already had access to financial markets to raise capital.
He said his country would continue to call out "bad actors" that exploited loopholes in these institutions for their own gain.
The US secretary of state was speaking at a conference hosted by the German Marshall Fund of the United States think thank. He is in Brussels for talks among foreign ministers at Nato.
Mr Trump has repeatedly accused European members of the military alliance of failing to spend enough on their own defence and relying too much on Washington.
Nato, meanwhile, is pressing the US president not to go through with his vow to withdraw from a 31-year-old nuclear treaty with Moscow and instead to work to bring Russia into compliance with the arms control pact.
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