Meta, Alphabet unit Google, Twitter and Microsoft have decided to take action against the misinformation spreading on their platforms.
This was agreed upon on Thursday. They will take a tougher line against disinformation including deep fakes and fake accounts under an updated EU code of practice or face hefty fines.
More than 30 signatories including advertising bodies have signed up for the updated Code of Practice on Disinformation, the European Commission said.
The signatories agree to do more to tackle deep fakes, fake accounts and political advertising while non-compliance can lead to fines of as much as 6% of a company's global turnover, the EU executive said.