"The West is winning and we're winning together," Pompeo said at the Munich Security Conference.

The annual gathering of world leaders, generals and diplomats to discuss security challenges has been dominated by fears of diminishing Western influence in the face of a more assertive China and Russia.

Pompeo spoke a day after German President Frank-Walter Steinmeier suggested the United States rejected "even the idea of an international community" and was acting "at the expense of neighbours and partners".

"Those statements don't reflect reality. I'm happy to report that the death of the transatlantic alliance is grossly over-exaggerated," Pompeo said, paraphrasing a famous Mark Twain quote.

He said Washington played a key role in keeping Europe safe by reinforcing NATO's eastern flank on the border with Russia, and had led a multinational effort to defeat the Islamic State jihadist group.

"Is this an America that 'rejects the international community'?" he asked.

"The free West has a brighter future than illiberal alternatives."

He also warned of the threats posed by Russia's territorial ambitions, China's military buildup in the South China Sea and Iran's "campaigns of terror" through proxy conflicts in the Middle East.

In a nod to concerns about European reliance on Russian natural gas, Pompeo also announced that the US would finance energy projects in eastern EU countries.

"The United States -- through our International Development Finance Corporation, and with the support of the US Congress -- intends to provide up to $1 billion in financing to the Central and Eastern European countries of the Three Seas Initiative," Pompeo told the conference.

"Our aim is to galvanise private sector investment in their energy sectors."

The pledge comes amid fierce US opposition to Russia's Nord Stream 2 pipeline, set to double the country's gas shipments to Germany.

Washington believes the pipeline will give Russia too much influence over security and economic issues in western Europe.