HONG KONG—China intensified the tit-for-tat trade battle with the U.S. on Thursday, with antitrust regulators warning that they have “hard to resolve” concerns about Qualcomm Inc.’s planned $44 billion purchase of NXP Semiconductors NV, potentially creating a stumbling block for the deal.
The move follows a decision by the U.S. Commerce Department to ban sales of American components to Chinese telecommunications company ZTE Corp., as well as threats from the White House to impose tariffs on $150 billion worth of Chinese goods...