Facebook CEO Mark Zuckerberg makes his keynote speech during Facebook Inc's annual F8 developers conference in San Jose, California, U.S., April 30, 2019. Stephen Lam | Reuters

Facebook, Google and Twitter ramped up their efforts to fight fake news ahead of elections last month but "more needs to be done" in the face of ongoing threats from Russia, EU officials said Friday. In a joint statement and report, the EU reported evidence of "coordinated inauthentic behavior" such as bots and fake accounts trying spread divisive content on online platforms ahead of the European Parliament elections at the end of May. The EU added it found "continued and sustained disinformation activity" by Russian sources aiming to influence voter preferences and suppress turnout. "The tactics used by internal and external actors, in particular linked to Russian sources, are evolving as quickly as the measures adopted by states and online platforms," the statement said. The EU report found it was too early to identify whether there was a "distinct cross-border disinformation campaign" targeting the European elections.

Social media platforms like Facebook, YouTube and Twitter have faced backlash from lawmakers around the world for failing to contain the spread of fake information in election campaigns. The EU said the companies have made progress in some of their efforts to fight disinformation, like hiring fact-checking teams and tightening restrictions around political advertising. But European officials added they expect the firms "to maintain momentum and to step up their efforts." The EU said that in the days preceding elections, more than 600 groups and Facebook pages across Germany, France, Italy, the U.K., Poland and Spain were reported to have spread disinformation and hate speech. It said these pages generated 763 million user views. Facebook has been stepping up its fight against fake accounts in recent months. In May, the company reported it removed 2.2 billion fake accounts in the first quarter of 2019, nearly double the amount from the prior quarter. Facebook also toughened its requirements around political advertising on the platform ahead of EU elections.