The EU says the initial €2.8 billion (£2.5bn) in charges are a response to the US decision to impose tariffs on European steel and aluminium imports.
The move risks escalating the nascent trade war between the US and the rest of the world, with Mr Trump ramping up protectionism and other countries hitting back.
“We did not want to be in this position. However, the unilateral and unjustified decision of the US to impose steel and aluminium tariffs on the EU means that we are left with no other choice,” Trade commissioner Cecilia Malmström said on Wednesday.
“The rules of international trade, which we have developed over the years hand in hand with our American partners, cannot be violated without a reaction from our side. Our response is measured, proportionate and fully in line with WTO rules. Needless to say, if the US removes its tariffs, our measures will also be removed.”
We did not want to be in this position
EU Trade commissioner Cecilia Malmström
The bloc says it has another €3.6 billion in US products lined up for further tariffs if the WTO trade court, where it has lodged a dispute, finds in its favour. The combined tariffs will be levied on diverse products such as Bourbon whiskey, cranberry juice, motorcycles, and denim trousers – as well as American metal exports.
Mr Trump hit EU, Canadian and and Mexican metal producers with tariffs of 25 per cent on steel and 10 per cent on aluminium at the start of June after a protracted battled over trade. The US president says the EU treats America “very unfairly”. He has also said he believed trade wars are “good, and easy to win”.
The EU’s retaliatory tariffs are only taking effect now because under WTO rules the bloc had to wait to impose them.
Relations between the US and the rest of the world sank further last week at the G7 summit in Canada after Mr Trump refused to endorse a joint communiqué by the leaders present.