The European Union has threatened to ban Elon Musk from Twitter unless the billionaire follows strict content moderation rules, sparking a regulatory row over the social media platform’s future, the Financial Times reported on Wednesday.

EU Industry Commissioner Thierry Breton made the threat during a video chat with Musk on Wednesday, the FT reported, citing people familiar with the conversation.

Breton told Musk that he must adhere to a list of rules, including abandoning an “arbitrary” approach to restoring banned users and agreeing to a “broad independent audit” of the platform by next year.

Later, according to a transcript of the conversation between the two, European Commissioner Thierry Breton told Musk that Twitter faced a “big job” to comply with European regulations.

“There is still a lot of work ahead, as Twitter will need to implement transparent policies for users, significantly strengthen content moderation and protect free speech, fight misinformation and limit targeted advertising,” Breton told Musk.

With these words, Musk and Breton “agreed that the Commission’s services will conduct a test” at Twitter’s headquarters in early 2023 to assess Twitter’s compliance with EU regulations.

Twitter and the EU did not immediately respond to Reuters’ request for comment.

Earlier, Breton called on Musk to comply with EU rules on fighting hate and disinformation online. European Union Justice Commissioner Didier Reynders also made similar comments.

Elon Musk on Tuesday announced a massive recovery of banned accounts and an end to the fight against Covid misinformation.