EU Commission spokesman Margaritas Schinas said it was ready to retaliate after Mr Trump attacked the bloc for its “very unfair trade policy” towards the United States.
During a frank ITV interview with Piers Morgan, Mr Trump warned the EU’s unfair treatment on American exporters would “morph into something very big” and “turn out to be very much to the EU’s detriment”.
Hitting back to the American leader’s comments, Mr Schinas said: “For us trade policy is not a zero sum game. It is not about winners and losers.
“We here in the European Union believe that trade can and should be win-win.
“We also believe that while trade has to be open and fair it also has to be rules-based.
“The European Union stands ready to react swiftly and appropriately in case our exports are affected by any restrictive trade measures by the United States.”
Washington is currently looking at a case to protect US economic interests on national security, including the imposition of import tariffs on steel and aluminium.
In a sensational interview with Mr Morgan, which aired on Sunday night, Donald Trump took a sharp jab at Brussels.
He said the EU was “was not cracked up to what it’s supposed to be”.
Mr Trump said: “I’ve had a lot of problems with European Union, and it may morph into something very big from that standpoint, from a trade standpoint.
“We cannot get our product in. It’s very, very tough. And yet they send their product to us – no taxes, very little taxes. It’s very unfair.
“They’re not the only one, by the way. I could name many countries and places that do. But the European Union has been very, very unfair to the United States. And I think it will turn out to be very much to their detriment.”