Three Americans who the State Department said were wrongfully detained in China for years are on their way back to the U.S. as part of a prisoner swap, a senior U.S. official with knowledge of the deal told ABC News.

China is releasing three Americans who were "wrongfully detained," a National Security Council spokesperson says.

Americans Mark Swidan, Kai Li and John Leung are en route back to the United States from imprisonment in China, the White House said.