On his last full day in office, Secretary of State Mike Pompeo declared that China had committed “genocide” and “crimes against humanity” through a campaign of internment, forced labor and forced sterilization of predominantly Muslim Uighurs in the Xinjiang region.

In an embarrassing blow to Beijing, Pompeo said Tuesday that the United States has documented a dramatic escalation in China’s “decades-long” campaign of repression against Uighurs and other ethnic and religious minorities since at least March 2017.

The “morally repugnant, wholesale policies, practices, and abuses are designed systematically to discriminate against and surveil ethnic [Uighurs] as a unique demographic and ethnic group, restrict their freedom to travel, emigrate, and attend schools, and deny other basic human rights of assembly, speech, and worship,” Pompeo said in a statement.

The 11th-hour determination means that the incoming Biden administration will largely have to deal with the diplomatic blowback from the decision, not the Trump administration. China denies accusations of mistreatment.

The determination does not force immediate sanctions or other penalties on China, but it may have implications for whether companies decide to do business in Xinjiang, which is a major supplier of cotton around the world.

The move is likely to put further strain on the world’s two largest economies, whose relations plunged to their lowest depths during the Trump administration.

China’s foreign ministry responded Wednesday by calling Pompeo a “doomsday clown” who spouted “lies” and said its Xinjiang policy promoted stability and prosperity.

“Genocide never happened, is not happening, and will not happen on China’s soil,” spokeswoman Hua Chunying said.

Pompeo has hailed the Trump administration as a truth-teller on U.S.-China relations and said that it came to this determination not because of “domestic political concern” but because “it is right.”

President Trump’s former national security adviser John Bolton, however, said Trump expressed approval for China’s use of Uighur concentration camps in Xinjiang during a meeting with Chinese President Xi Jinping.

“Trump said that Xi should go ahead with building the camps, which Trump thought was exactly the right thing to do,” Bolton wrote in his memoir “The Room Where It Happened.” The administration has denied this account.

The State Department decision follows the passage of legislation by Congress on Dec. 27 requiring the United States to make a finding within 90 days about whether China’s practices in Xinjiang constitute crimes against humanity or genocide.

“It’s an indication of serious concern, but that it’s coming literally less than 24 hours to go in this administration . . . in some ways undermines that message,” said Sophie Richardson, a specialist on China issues at Human Rights Watch.

Missy Ryan and Gerry Shih contributed to this report.