A senior European Union official warned Elon Musk on Wednesday that Twitter needs to strengthen measures to protect users from hate speech, misinformation, and other harmful content to avoid violating new rules that threaten tech giants with hefty fines or even bans in 27 countries.

Thierry Breton, the European Union Commissioner for Digital Policy, told the Tesla billionaire executive that the social media platform will have to significantly increase efforts to comply with the new rules, known as the Digital Services Act, which is set to take effect next year.

The two also held a video call to discuss Twitter's readiness for the law, which will require tech companies to better monitor their platforms for materials that, for example, promote terrorism, child sexual abuse, hate speech, and commercial fraud.

It is part of a new digital rulebook that has made Europe a global leader in curbing the power of social media companies, which could lead to a clash with Musk’s vision for a freer Twitter. U.S. Treasury Secretary Janet Yellen said on Wednesday that an investigation into Musk's $44 billion purchase was not on the table.

Also, Musk said, according to a reading of the call issued by Breton’s office: "But let’s also be clear that there is still massive work ahead of us. Twitter will need to implement transparent user policies, greatly enhance content oversight and protect freedom of expression, firmly address misinformation, and limit targeted advertising."

After Musk, who describes himself as an "absolute free speech absolutist," bought Twitter a month ago, groups monitoring the platform for racist, anti-Semitic, and other toxic speech, such as the Online Civil Rights Initiative, said such content is increasing worldwide.

Musk also indicated his interest in rolling back many of Twitter’s previous rules aimed at combating misinformation, the latest being the abandonment of the COVID-19 misinformation policy. He has already reinstated some prominent accounts that violated Twitter’s content rules and promised a "general amnesty" to restore most suspended accounts starting this week.