The European Union has long been calling on tech companies to do more when it comes to tackling online hate speech. Earlier this year, four of the biggest firms – Facebook, Microsoft, YouTube, and Twitter – signed up to a voluntary code of conduct that would see them review and, if necessary, remove such material within 24 hours of being notified. But the EU says they aren’t sticking to their promise.

Reuters reports that a review conducted by EU Justice Commissioner Vera Jourova found less than half the cases of online hate speech were being addressed within the 24-hour time period agreed on.

"In practice the companies take longer and do not yet achieve this goal. They only reviewed 40 percent of the recorded cases in less than 24 hours," a Commission official said. "After 48 hours the figure is more than 80 percent. This shows that the target can realistically be achieved, but this will need much stronger efforts by the IT companies."

According to The Financial Times, YouTube was the fastest of the four companies to respond to complaints, while Twitter was the slowest. Additionally, the removal rates of racist posts differed across Europe; in Germany and France it was 50 percent, while in Austria it was 11 percent, and just 4 percent in Italy.

Jourova warned that if things don’t improve, the companies could face new laws that force them to act faster."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."

The refugee crisis, terrorist bombings, and the rise of several far-right groups have contributed to the increase in hateful online material appearing across Europe recently. Back in May, Facebook, YouTube, and Twitter were sued by several French rights groups for failing to remove racist, anti-semitic and homophobic content.