Donald Trump has threatened the European Union with additional and “substantial” tariffs after Brussels imposed a series of steep fines on US tech giants.

The US president accused Brussels of taking “direct aim” at several American companies including Apple, Meta Platforms, Amazon and Google, writing in a Truth Social post: “The United States of America is not a ‘PIGGYBANK’ for Europe, nor will we allow it to be!”

Days earlier, Google was fined €890m ($1bn) by the EU after its search and app store services were found to have breached online competition laws. Last year Apple and Meta, the owner of Facebook and Instagram, were also fined.

Trump claimed in his social media post on Friday that the US would “immediately” launch an investigation into the EU’s practice of “‘ROBBING’ American Companies and, in turn, the American Taxpayer,” and said that the EU will “pay a very big price” for its actions.

It came just a day after the Trump administration separately imposed a sweeping round of tariffs on more than 80 countries, including those in the EU.

The European Commission did not immediately comment on Trump’s threat on Friday. Announcing the fine on Google on Wednesday, it said the tech company had given “preferential treatment to its own services, including shopping, hotels, transport and sports results”.

Google welcomed Trump’s intervention on Friday.

Jose Castaneda, a spokesperson for the company, said Google had worked hard to comply with the EU’s Digital Markets Act and expressed its concerns about the effects of recent decisions by the European Commission. “We appreciate the engagement by the administration and U.S. government,” he said.

Trump has often used tariffs – or simply the threat of them – as a way to retaliate against countries for decisions outside trade policy. Last year, he threatened a tax on imports from Mexico and Canada until the two countries agreed to implement measures on border security.

Despite challenges from the supreme court, Trump has persisted in implementing tariffs globally, claiming that they will help boost US jobs and manufacturing. The tariffs he announced yesterday would impose a 10% levy on the EU, and were designed to clamp down on what Trump claimed were unfair labor practices.

The EU has cracked down on a handful of large tech companies since before the start of Trump’s presidency after passing the Digital Markets Act, meant to help regulate competition among digital media companies.