The Trump administration is seeking to join Elon Musk’s appeal against a €120 million EU fine of the billionaire’s social media platform X, the latest escalation in the transatlantic clash over Brussels’ efforts to rein in US tech companies.

The US Department of Justice on Thursday filed an application to intervene in a pair of cases brought by Musk and X seeking annulment of the penalty, which will be heard at the EU’s General Court in Luxembourg.

“The European Commission inappropriately attempted to expand its regulatory authority to reach American companies not present or operating within its jurisdiction,” assistant attorney general Brett Shumate said.

“We will not tolerate the European Commission engaging in regulatory over-reach to try and control American engines of innovation and economic growth,” Shumate added.

The European Commission in December last year fined X €120 million for breaking the Digital Services Act, the first such penalty under the bloc’s online safety regime. It accused the platform of breaching its regulations for transparency, providing insufficient access to data and the deceptive design of its blue-tick system for verified accounts.

The DSA, a more aggressive set of rules to police online players, has become a flashpoint between Brussels and US tech companies. Donald Trump’s administration has supported claims by US companies that the EU is unfairly targeting American groups and infringing freedom of speech principles championed by the Maga movement.