The European Union has responded defiantly to a warning that the US could impose new fees and restrictions on EU service providers.

The United States framed its threat — part of a growing trans-Atlantic row between the two sides over the EU's Digital Markets Act — as a response to the EU's "discriminatory" legislation, fines and taxes on US companies.

In a post on X, the Office of the US Trade Representative said the EU and some member states had engaged in "discriminatory and harassing lawsuits, taxes, fines and directives against US service providers".

The trade representative said the activities, which included EU regulators imposing a 120 million euro ($141.57 million) fine on the social media platform X earlier this month and a 2.95 billion euro demand on Google earlier this year, came as EU companies had operated "freely" in the US.

Mentioning EU companies that operate in the US, such as Accenture, DHL and Siemens, the trade representative added, "If the EU and EU member states insist on continuing to restrict, limit, and deter the competitiveness of US service providers through discriminatory means, the United States will have no choice but to begin using every tool at its disposal to counter these unreasonable measures."

US law allows for the imposition of a wide range of fees and other restrictions against foreign service providers, it said. "The United States will take a similar approach to other countries that pursue an EU-style strategy in this area."

The EU hit back through its executive branch, the European Commission, by saying its rules "apply equally and fairly to all companies operating in the EU" and insisting that its Digital Markets Act is aimed at protecting users' privacy and ensuring free competition.

Level playing field

European Commission spokesman Thomas Regnier told Reuters that the EU's rules exist to ensure "a safe, fair and level playing field in the EU, in line with the expectations of our citizens".

He said the bloc is "implementing the commitments in the EU-US Joint Statement" on trade that was agreed in August, and that it continues to talk to Washington about other trade issues.

Euronews reported that the US Trade Representative's threat could end up doing little to guarantee US companies more access to EU markets because it may now anger and embolden "actual anti-Americans" and silence "moderates" within the bloc.

News TV network France 24 said the row could also inspire other countries to introduce similar legislation to the EU's Digital Markets Act.

US President Donald Trump has been a strong critic of EU laws, claiming the fines that have been levied against US technology companies have diverted money away from US jobs and investments. He has also reportedly told US diplomats stationed in Europe to lobby EU lawmakers to dilute the act.