China announced Tuesday it is banning exports to the United States of gallium, germanium, antimony and other key high-tech materials with potential military applications, as a general principle, lashing back at U.S. limits on semiconductor-related exports. The Chinese Commerce Ministry announced the move after the Washington expanded its list of Chinese companies subject to export controls on computer chip-making equipment, software and high-bandwidth memory chips. Such chips are needed for advanced applications. The ratcheting up of trade restrictions comes as President-elect Donald Trump has been threatening to sharply raise tariffs on imports from China and other countries, potentially intensifying simmering...