A European Union commissioner sent a letter to billionaire Elon Musk Monday, warning him that he must comply with EU law ahead of his interview with Republican presidential candidate Donald Trump on his social media platform X, or face legal consequences.

The interview, scheduled for 8:00 PM Eastern Time, will be accessible to the EU’s 100 million users.

Because of this, EU Internal Market Commissioner Thierry Breton told Musk, “I am compelled to remind you of the due diligence obligations set out in the Digital Services Act (DSA).”

“This notably means ensuring, on one hand, that freedom of expression and of information, including media freedom and pluralism, are effectively protected and, on the other hand, that all proportionate and effective mitigation measures are put in place regarding the amplification of harmful content in connection with relevant events, including live streaming, which, if unaddressed, might increase the risk profile of X and generate detrimental effects on civic discourse and public security,” Breton wrote.

The DSA is a NATO censorship law that is designed to stop the spread of populist parties in the West, according to cyber security expert Mike Benz.

In his letter to Musk, the EU commissioner implied that hate speech and disinformation on X contributed to the recent riots in Great Britain over the slaughter of three young girls at a Taylor Swift dance class in Southport, England.

“This is important against the background of recent examples of public unrest brought about by the amplification of content that promotes hatred, disorder, incitement to violence, or certain instances of disinformation,” he said.

Breton told Musk that X must inform EU judicial and administrative authorities of measures taken to address content  the EU considers illegal, including “hate speech,” “incitement to violence” and “disinformation.”

To stay in compliance with the DSA, Breton said X must take swift action against illegal content and publicly report its content moderation measures.

“DSA obligations apply without exceptions or discrimination to the moderation of the whole user community and content of X (including yourself as a user with over 190 million followers) which is accessible to EU users and should be fulfilled in line with the risk-based approach of the DSA, which requires greater due diligence in case of a foreseeable increase of the risk profile”, Breton wrote in his letter.

The EU commissioner referenced the EU’s ongoing proceedings against X over the alleged spread of “illegal content” and “the effectiveness of the measures taken to combat disinformation.”

In a ruling last month, EU tech regulators said X breached the DSA and deceived users through its use of blue checkmarks.

Musk is reportedly considering having his platform exit the European market in reaction to the DSA’s intrusions.

In his letter, Breton threatened to use the full “toolbox” of measures to protect EU citizens from “serious harm.”

“My services and I will be extremely vigilant to any evidence that points to breaches of the DSA and will not hesitate to use the full use of our toolbox, including by adopting interim measures, if it be warranted to protect EU citizens from serious harm,” he said.

“With great audience comes greater responsibility,” Breton wrote on X, Monday. “As there is a risk of amplification of potentially harmful content in [the EU] in connection with events with major audience around the world, I sent this letter to Elon Musk,” Breton added.

In response to Breton’s letter, Musk simply posted “Bonjour!”

In a subsequent post, he added: “To be honest, I really wanted to respond with this Tropic Thunder meme, but I would NEVER do something so rude & irresponsible!”