A huge network of accounts has been found spreading fake information on Facebook, a campaign group has claimed.
Disinformation pages being hosted across Europe and seen hundreds of millions of times were being spread over the site, an investigation by Avaaz found.
Many of the pages were focused on spreading far-right stories, the campaign group said. They were discovered in France, UK, Germany, Spain, Italy and Poland, it said.
Racist and anti-immigration content featured prominently on the pages, the researchers said. Most of them contained information that was entirely false, promoting conspiracy theories and widely debunked stories.
One post included a video showing migrants in Italy destroying a police car. This was seen by 10 million people, but the video was fake, it's footage taken from a film.
Other posts shared on more than 500 pages spread similar false stories about migrants and the European Union.
The pages have since been removed by Facebook.
The social media giant has been attempting to promote its efforts to remove such fake stories and propaganda accounts.
It recently took journalists on a tour of a "war room", set up specifically to fight disinformation around the European elections. But it remains unclear how effective the sites attempts to address the problem have proven.
But before the fake accounts were taken down, they managed to gather more than 13 million interactions and 6 million followers, Avaaz said.
That makes them far more widespread than the pages of the public far-right and anti-EU parties put together,
“With days to go until EU elections, Europe is drowning in disinformation," said Avaaz's campaign director Christoph Schott. "The size and sophistication of these networks makes them weapons of mass destruction for democracy, and right now they are pointed squarely at Europe. The most worrying thing is we’ve just scratched the surface. There could be much, much more out there.
“Disinformation is being used to deceive people and stoke anger and distrust in our politics, and the concern is that we’ll see the impact in the European elections this week.”