A top European Union official warned Elon Musk on Wednesday that Twitter needs to beef up measures to protect users from hate speech, misinformation and other harmful content to avoid violating new rules that threaten tech giants with big fines or even a ban in the 27-nation bloc.

Thierry Breton, the EU’s commissioner for digital policy, told the billionaire Tesla CEO that the social media platform will have to significantly increase efforts to comply with the new rules, known as the Digital Services Act, set to take effect next year.

The two held a video call to discuss Twitter’s preparedness for the law, which will require tech companies to better police their platforms for material that, for instance, promotes terrorism, child sexual abuse, hate speech and commercial scams, Associated Press reported.

It’s part of a new digital rulebook that has made Europe the global leader in the push to rein in the power of social media companies, potentially setting up a clash with Musk’s vision for a more unfettered Twitter. U.S. Treasury Secretary Janet Yellen also said Wednesday that an investigation into Musk’s $44 billion purchase was not off the table.

Breton said he was pleased to hear that Musk considers the EU rules “a sensible approach to implement on a worldwide basis.”