London (CNN Business) Far-right and anti-EU groups have been using hundreds of "disinformation networks" on Facebook to spread their message ahead of this week's European Union elections, according to campaign group Avaaz.

The group said its investigation had identified over 500 suspicious pages andgroups in France, Germany, Italy, Poland, Spain, and the United Kingdom. Duplicate and fake accounts were used to spread the content wider, it added.

Content posted by the pages had been viewed 533 million times over the past three months, Avaaz said. It included doctored images, fake news stories, posts promoting white nationalism, pages supporting banned individuals and groups and hateful content inciting violence against Muslims.

Some of the content, including symbols associated with Nazism in Germany, was illegal.

Avaaz shared its findings with, which reacted by deleting some of the accounts.

A Facebook spokesperson said the company removed a "number of fake and duplicate accounts" that were violating its policies.

"We also took action against some additional pages that repeatedly posted misinformation," the spokesperson added.

350 million people from 28 European Union member states will be More than350 million people from 28 European Union member states will be able to cast their votes for European Parliament candidates later this week.

Euroskeptic and fringe parties are expected to do well in the election. The most recent polling from Europe Elects predicts that these parties could win up to 35% of seats in the European Parliament.

Avaaz said the fake news pages and groups were followed by nearly 32 million people, far more than the number of followers of the official Facebook pages of the main far-right parties in the six countries combined.

Correction: This story has been updated to correct the number of eligible EU voters.