The European Union (EU) and Mexico have expressed disappointment at US President Donald Trump's threat to impose 30% tariffs on their imports from 1 August.
Mexico criticised what it called Trump's "unfair deal" and insisted its sovereignty was non-negotiable, while the EU's chief, Ursula von der Leyen threatened to take "proportionate countermeasures", if needed. Both said they wanted to keep negotiating with the US.
Trump has warned he will impose even higher import taxes if either of the US trading partners decide to retaliate.
This week Trump also announced new tariffs on goods from Japan, South Korea, Canada and Brazil from next month.
In the letter sent on Friday to European Commission President Ursula von der Leyen, Trump wrote: "We have had years to discuss our trading relationship with the European Union, and have concluded that we must move away from these long-term-large, and persistent, trade deficits, engendered by your tariff, and non-tariff, policies and trade barriers.
"Our relationship has been, unfortunately, far from reciprocal," the letter added.
In his letters to the EU and Mexico, Trump warned that if either trade partner retaliated with import duties of their own against the US, he would hit back by raising tariffs by a similar percentage over and above the 30%.
In a pre-recorded interview with Fox News which aired on Saturday night, President Trump said some countries were "very upset now" but he insisted the tariffs meant "hundreds of billions of dollars" were "pouring in".
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.
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 a 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."
Trump's letter did not say if Mexican 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 - composed of 27 countries.
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 as negotiations with others continue.
