The European Union estimates that the first wave of Donald Trump’s steel and aluminum tariffs will hit as much as €28 billion ($29.3 billion) of the bloc’s exports in what would be a massive escalation in the US president’s trade war.

Donald Trump’s tariffs are a headache for all his trade partners. But the U.S. president’s plan to impose ad hoc “reciprocal” levies on imports are a particular problem for the European Union. By enabling him to target whichever countries in the bloc he pleases,

European Commission President Ursula von der Leyen said during the Munich security conference Friday the European Union will respond if the United States imposes reciprocal tariffs.

The European Commission is investigating whether to tighten its current system of quotas on steel imports to protect EU producers from new tariffs U.S. President Donald Trump plans to impose on incoming steel and aluminium on March 12.

The amount of goods would be about four times larger than the last time Trump targeted the bloc’s metals sector.

The European Union estimated that the first wave of tariffs on steel and aluminium imposed by US President Donald Trump will result in a hit to EU exports worth up to €28 billion (approx. US$29.3 billion).