Washington — The National Basketball Association has severed ties to a training center in China's western Xinjiang region, where Beijing faces growing international condemnation over its treatment of minorities. The NBA statements were contained in the letter dated July 21 to Blackburn that was posted on her official Senate webpage Wednesday. Signed by NBA Deputy Commissioner Mark Tatum, it was sent in response to questions raised by Blackburn about NBA involvement in Xinjiang, described by the senator as "one of the world's worst humanitarian zones". China is in the midst of a bitter falling out with the United States on a range of fronts, including human rights, trade and Hong Kong. "The financial impact of NBA games not airing on television in China has been significant," Tatum wrote.