Trump stood next to the U.K's prime minister and expressed full-throated support for the racist belief that immigration is wrong.

Trump brought his virulent white supremacist message to the international stage Friday, claiming immigration is wiping out European culture, an argument central to the racist movement. He even threatened Europe’s immigrants, saying “they better watch themselves.”

The comments came as Trump stood shoulder-to-shoulder with U.K. prime minister Theresa May at a joint press conference.

When a reporter asked Trump about his comments to the Sun newspaper attacking immigration, Trump defended and reiterated his racist sentiments.

Immigration “has been very bad for Europe,” Trump said, and added, “I think it’s changing the culture, I think it’s a negative thing for Europe. I think it’s very negative.”

He went on to say that immigration has “very much hurt Germany” and “other parts of Europe.”

“They better watch themselves,” he warned, “because you are changing culture.”

He also described immigration to Europe as “sad” and “unfortunate” and connected it directly to international terrorism.

This is a white supremacist point of view. White supremacists have regularly cited migration to Europe from the Middle East and Africa as a point of concern, and the same message has been echoed in the U.S.

Trump campaigned and governs on this racist message, characterizing Mexicans as “rapists,” calling Latino immigrants “animals,” and pushing for a ban on Muslim travel to the U.S.

Many of the white supremacist ideas Trump has embraced from the presidency were whipped up by Steve Bannon at Breitbart, who then became Trump’s campaign chairman and senior White House aide.

The comments with May again marked a departure from the American tradition of welcoming immigrants to the country. Trump himself is a descendant of immigrants, as are most Americans.

But Trump is also a white supremacist who believes  other white supremacists, and neo-Nazis, are “very fine people.”

Speaking in the country that was threatened by Nazi invasion over 70 years ago, Trump switched sides. Instead of opposing the racist ideals thousands of soldiers died fighting, Trump embraced racism once again.