President Biden on Wednesday called longtime ally Japan "xenophobic," along with China and Russia, blaming their economies' recent performances on racial prejudice. 

The president made those remarks during an off-camera fundraiser to mark the beginning of Asian American and Pacific Islander heritage month in Washington, D.C., three weeks after he hosted Japanese Prime Minister Fumio Kishida and his wife for an elaborate state dinner at the White House. 

"You know, one of the reasons why our economy is growing is because of you and many others —why?" the president said. "Because we welcome immigrants. We look to — the reason — look, think about it. Why is China stalling so bad economically? Why is Japan having trouble? Why is Russia? ... Because they're xenophobic. They don't want immigrants. Immigrants are what makes us strong! Not a joke. That's not hyperbole. Because we have an influx of workers who want to be here and contribute. This community's vote will be critical in —  from Virginia to George to Nevada. I know we could do a lot together. A lot more."

White House press secretary Karine Jean-Pierre, speaking with reporters aboard Air Force One Thursday, said the "president was very clear" about what he said. America, she said, is stronger because of immigrants. 

It's not clear how the president's off-camera comments will land with Japanese officials. Last month, when Mr. Biden hosted Kishida, he called the two nations' ties "unbreakable," and said the two nations share the "same values, the same commitment to democracy and freedom to dignity."

Japan has the lowest immigration rate of the Group of Seven advanced economies. No more than 2% of its population are immigrants.

In the U.S., foreign-born immigrants make up about 14% of the population, according to the Census Bureau. 

Kathryn Watson is a politics reporter for CBS News Digital based in Washington, D.C.