Donald Trump has threatened the European Union with “substantial” tariffs after Brussels imposed a series of steep fines on US tech giants.In a post on his Truth Social platform, the US president wrote: “The United States of America is not a ‘PIGGYBANK’ for Europe, nor will we allow it to be!”It comes days after Google was fined €890m by the EU after its search and app store services were found to have breached online competition laws.The US will “immediately” launch an investigation “into the practice of ‘ROBBING’ American Companies and, in turn, the American Taxpayer”, Trump said. “The European Union will pay a very big price for this illegal and highly unethical conduct, which I have consistently warned them about.”More details soon …