The European Commission this week called on Facebook, Twitter, and other major tech companies to more aggressively police online hate speech or else face new legislation that would force them to do so. As the Financial Times reports, a study commissioned by Věra Jourová, the EU justice commissioner, found that Facebook, Twitter, Google, YouTube, and Microsoft have largely struggled to comply with a voluntary code of conduct on hate speech announced earlier this year.

European governments have pressured tech companies to more proactively curb hate speech and incitement to terrorism, amid heightened racial tensions and national security concerns. The government-led effort has been particularly aggressive in Germany, where the ongoing refugee crisis has sparked a xenophobic backlash that has reinvigorated the far-right. German Justice Minister Heiko Maas recently said that Facebook should be treated as a media company, which would make it liable for any hate speech published to its platform.

Under a code of conduct announced in May, Facebook, Twitter, Google, and Microsoft agreed to review and respond to “the majority” of hate speech complaints within 24 hours. According to the commission’s report, however, only 40 percent of recorded incidents were reviewed within 24 hours. After 48 hours, that figure rose to 80 percent, according to both the Financial Times and Reuters.

“This shows that the target can realistically be achieved, but this will need much stronger efforts by the IT companies," a commission official told Reuters. The code of conduct has come under criticism from rights groups who have argued that it delegates disproportionate responsibility to private companies, rather than governments.

Among the tech companies that agreed to the code of conduct, YouTube was the fastest to respond to complaints, while Twitter was the slowest, according to the Financial Times. Removal rates were above 50 percent in France and Germany, but just 11 percent and 4 percent in Austria and Italy, respectively.

Speaking to the Financial Times, Jourová said that tech companies may face new laws to curb hate speech if their voluntary efforts prove unsatisfactory. EU justice ministers will meet on Thursday to discuss the report’s findings.

“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,” Jourová told the newspaper.