The EU has been a frequent target of Trump’s criticism. On 2 April, he proposed a 20% tariff for goods from the bloc, as well as dozens of other trade partners. He then threatened to raise the EU import taxes to 50% as trade talks stalled.

Washington and Brussels had hoped to reach an agreement before a deadline of 9 July, but there have been no announcements on progress.

In 2024, the US trade deficit with the bloc was $235.6bn (€202bn; £174bn), according to the office of the US trade representative.

Von der Leyen said the EU remained ready “to continue working towards an agreement by Aug 1”.

“We will take all necessary steps to safeguard EU interests, including the adoption of proportionate countermeasures if required,” von der Leyen said.

“Few economies in the world match the European Union’s level of openness and adherence to fair trading practices,” her statement added.

The 27-member EU said earlier this week it hoped to agree a deal with Washington before 1 August.

France’s President Emmanuel Macron said he was in “very strong disapproval” of Trump’s announcement.

If no agreement is reached, the French leader suggested the EU plan “speeding up the preparation of credible countermeasures”.

Bernd Lange, the head of the European Parliament’s trade committee, described Trump’s move as “a slap in the face for the negotiations”.

He said that it was “no way to deal with a key trading partner,” adding said Brussels should enact countermeasures as soon as Monday.

Some EU leaders called for as deal with Trump. Italian Prime Minister Giorgia Meloni said in a statement she trusted “a fair agreement” could be reached, adding: “It would make no sense to trigger a trade war between the two sides of the Atlantic.”

Dutch Prime Minister Dick Schoof said on social media that the EU “must remain united and resolute” in its aim to reach a “mutually beneficial” deal with the US.

Germany’s Association of the Automotive Industry warned about the prospect of rising costs for German carmakers and suppliers, and said it was “regrettable that there is a threat of a further escalation of the trade conflict”.

In his letter to Mexico’s leader, Trump said the country had not done enough to stop North America becoming a “Narco-Trafficking Playground”.

“Mexico has been helping me secure the border, BUT, what Mexico has done, is not enough,” Trump added.

Mexican President Claudia Sheinbaum expressed confidence that a deal could be reached.

“We believe, based on what our colleagues discussed yesterday, that we will reach an agreement with the USA and that we will, of course, achieve better conditions,” Sheinbaum said on Saturday.

“We are clear on what we can work with the USA and we are clear on what we cannot,” she added. “And there is something that is never negotiated, ever, and that is the sovereignty of our country”.

Earlier on Saturday, the Mexican economy and foreign ministries called Trump’s tariffs an “unfair deal” in a joint statement.

Trump’s letter did not say if Mexico goods traded within the 2020 United States-Mexico-Canada Agreement would be exempt from the proposed 1 August tariff hikes, as the White House said would be the case with Canada.

Earlier this week, the White House sent a letter to Canada threatening a 35% tariff.

As of Saturday, the Trump administration has now proposed tariff conditions on 24 countries and the EU.

On 12 April, White House trade adviser Peter Navarro set a goal to secure “90 deals in 90 days”.

So far, the president has announced the outlines of two such pacts with the United Kingdom and Vietnam amid ongoing negotiations.