Lighthizer, who campaigned with President Trump, serves as an unofficial adviser. He was reportedly passed over for Treasury secretary, but he remains close to the president. Lighthizer says U.S. trade with China has largely benefited an adversary who has engaged in stealing trade secrets and other malicious actions.

China's sharpest pushback on Sunday was over fentanyl, an area where the Biden administration had also been urging Beijing to crack down on shipments.