The European Union is broadening the list of US goods it will target with retaliatory tariffs if US President Donald Trump follows through on his threat to impose duties on steel and aluminum exports,

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,

Trade specialists have expressed that discussions with Western trade allies may gain new energy due to the instability introduced into the global trade system by the US. In addition to close trade associates like Canada and Mexico, Trump has also issued tariff threats towards the EU.

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.

President Donald Trump’s tariffs on aluminum and steel imports are mostly driven by concerns that China is glutting global markets and hurting U.S. manufacturing, a former trade adviser to the White House said.