The US government is trying to get Elon Musk and his social media platform X out of a $137 million fine by the European Union in an escalation of its criticism of the bloc’s tech rules.

The US Department of Justice said it had filed an application with the help of the Department of State to support a legal challenge by Musk to annul the case in the EU’s General Court. The Luxembourg-based court will now decide whether the US has a right to intervene.

The US government is arguing that it should be involved in the case to protect American companies. The fine is precedent-setting as the bloc’s first sanction under the Digital Services Act, which requires online platforms to do more to tackle illegal and harmful content, especially the largest sites. Many of those, which include Meta’s Facebook and Instagram, Google’s YouTube, and Microsoft’s LinkedIn, are headquartered in the US and contribute significantly to the US economy, it pointed out.

“We will not tolerate the European Commission engaging in regulatory overreach to try and control American engines of innovation and economic growth,” said Assistant Attorney General Brett A. Shumate of the Justice Department’s Civil Division.

The case also has “implications” for US-EU relations, it warned. The act has become a major source of tension between officials, with US President Donald Trump calling the penalties “overseas extortion.” Last year, he threatened imposing tariffs on any country implementing digital regulation, which he said were “all designed to harm, or discriminate against, American technology.” Vice President JD Vance has criticized the DS’s content moderation rules as “authoritarian censorship.”

The European Commission slapped X with the €120 million fine in December following a two-year-long investigation which found X had breached transparency obligations. Claiming users with blue checkmarks are “verified accounts” when they simply have to pay for the status is deceptive, the Commission ruled. X’s inaccessible and incomplete advertising repository and failure to provide access to public data for researchers is also hindering research into the platform’s risks, it said. In July, the Commission accepted X’s plan to fix the data access issues, which X now has six months to implement.

Both Musk and X launched appeals against the ruling on behalf of both parties in February. The EU’s investigation was “incomplete and superficial” and the interpretation of the DSA obligations “tortured,” they said. They also complained they had not been given “rights of defence … suggesting prosecutorial bias.”

Musk has also complained about the financial and administrative burden of heightened transparency requirements as governments globally try to get a better understanding of—and limit—social media platforms’ risks of harm. In July, he argued Australia’s “invasive” information-gathering powers within the country’s under-16 social media ban interfered with international law. At the time, professor of internet law at Queen Mary University of London, Julia Hörnle, told WIRED that Australian regulators were within their rights to order disclosures related to a company’s operations in that particular country.