The United States has accused the Chinese of genocide against the Muslim Uyghur minority.
The unprecedentedly fierce swipe comes from the American foreign minister Pompeo, on his last full day in office.
The minister says that the rulers in China are committing crimes against humanity and genocide in Xinjiang. They would be directed against the Uyghurs, but also against other minorities.
Pompeo called the Chinese action an insult to the Chinese people and civilized countries around the world. He warned of the consequences of Chinese influence in the free world. China and the communist regime should be held accountable, he says.
Pompeo is serving under Republican President Trump, who will be succeeded by Democrat Biden on Wednesday.