California Governor Gavin Newsom on Tuesday criticized European political leaders for what he described as their "complicity" in failing to stand up to U.S. President Donald Trump's demands regarding Greenland.

"It's time to buck up, it's time to get serious and stop being complicit," Newsom told reporters during a visit to the World Economic Forum in Davos, Switzerland. "It's time to stand tall and firm, have a backbone," he said.

The Democratic governor posted his words on X, sharing two video clips accompanied by statements reading, "To our allies: Stand firm. Stand tall. Stand united," and "America's allies and business leaders need to understand this: There's no diplomacy with Donald Trump. Get off your knees and grow a spine."

Newsom said that he "can't take this complicity. People rolling over. I should have brought kneepads for all the world leaders ... this is pathetic."

"The Europeans should decide for themselves what to do. But one thing they can't do is what they've been doing. And they've been played. This guy is playing folks for fools," he added.