The EU's top trade official said the bloc would have no choice but to hit back after Washington imposed tariffs on a record $7.5-billion worth of European Union goods on Friday.
"We regret the choice of the US to move ahead with tariffs," European Trade Commissioner Cecilia Malmstrom said in a statement after attempts to negotiate a truce went nowhere.
"This step leaves us no alternative but to follow through in due course with our own tariffs in the Boeing case, where the US has been found in breach of WTO rules," she added.
