The deal suggests a willingness by Beijing to engage with the Biden administration before Donald Trump's return to the White House.

The State Department announced the release of Mark Swidan, Kai Li and John Leung. A U.S. government official told NBC News the three were exchanged for two Chinese detainees.

The Chinese government also announced Thursday that the U.S. had returned four people to China, including at least three Chinese citizens who it said had been held for “political purposes,” and a person who had been sought by Beijing for crimes and had been living in the United States. It did not identify the four.