The European Commission thinks American tech companies — Microsoft, Twitter, Google, and Facebook, in particular — are doing a poor job of fighting hate speech online, and it’s demanding more action.

In May, the four companies signed a “voluntary code of conduct” with the European Union, agreeing to take some concrete steps toward dealing with racism and hate on their services. This included promises to handle reported incidents within 24 hours and increased staff training “on current societal developments.”

According to EU justice commissioner Vera Jourova, Silicon Valley hasn’t followed through.

“The last weeks and months have shown that social media companies need to live up to their important role and take up their share of responsibility when it comes to phenomena like online radicalization, illegal hate speech, or fake news,” Jourova told the Financial Times in an interview published Sunday.

Jourova’s remarks come after an incredibly tense few months for U.S. tech companies in Europe, with developments including a $14.5 billion back-tax bill for Apple, a potential criminal probe of Facebook in Germany for hate-speech law violations, and a tidal wave of fake and suspiciously pro-Kremlin news on social media.

The Times additionally reports that a new survey prepared for Jourova shows that 40 percent of incidents were “reviewed within 24 hours,” and that 80 percent were examined within 48 hours; the commission also found that YouTube is the fastest to respond to incidents, while Twitter is the slowest.

Furthermore, according to Jourova, if these companies don’t improve their responsiveness, the EU will take steps to force changes.

“If Facebook, YouTube, Twitter, and Microsoft want to convince me and the ministers that the non-legislative approach can work, they will have to act quickly and make a strong effort in the coming months,” Jourova added.