The European Union will have to take decisive action if the United States enacts tariffs on its exports, Danish Prime Minister Mette Frederiksen cautioned on Monday.

US President Donald Trump has threatened to impose tariffs on the EU unless the bloc significantly reduces its trade deficit by increasing its imports of American oil and gas. On Friday, Trump reiterated his stance, asserting that he is “absolutely” planning to impose tariffs on the EU, claiming that the bloc has treated the US poorly in terms of trade practices. However, he has yet to specify which goods would be affected or the exact tariff rates.

In remarks to reporters prior to an informal gathering of EU leaders in Brussels, Frederiksen expressed concern that Trump’s push for tariffs could lead to a trade war.

“I do not support a trade war. In fact, I advocate for the opposite—enhanced trade between us. However, it is evident that if there is significant American pressure on the European market, we will have no choice but to respond firmly,” she remarked.

“Regrettably, we will need to provide a very strong response” to any US tariffs, Frederiksen noted, although she did not reveal the specifics of that response. She did emphasize that the EU’s countermeasures would likely have repercussions for everyday citizens.

The situation will impact employees and businesses across the US, Europe, Canada, and other involved regions, she noted.

Similar sentiments were echoed by Frederiksen’s counterparts in the EU. French President Emmanuel Macron stated that if the bloc faces trade aggression, it must defend itself and respond accordingly. Luxembourg’s Prime Minister, Luc Frieden, indicated that the appropriate response to tariffs would be to take reciprocal action. Meanwhile, Polish Prime Minister Donald Tusk emphasized the importance of avoiding “entirely unnecessary and foolish tariff wars.”

Trump has already acted on some of his previous tariff threats. Recently, he declared a substantial 25% duty on all imports from Mexico and most products from Canada, along with a 10% tariff on Chinese goods, set to take effect on February 4. He defended these actions by accusing the three nations of not adequately addressing the influx of migrants and illegal drugs into the US. In response, Canada has imposed a 25% tariff on US goods and has warned of additional counteractions. Mexico has also indicated plans for retaliatory tariffs, while China announced its intention to challenge Trump’s tariffs through the World Trade Organization.