Alphabet Inc unit Google, Facebook Inc (META), Twitter Inc, and other tech companies will now have to take strict measures against the deepfakes and fake accounts on their platforms or risk hefty fines under an updated European Union code of practice, according to an EU document seen by Reuters.

Deepfakes are hyperrealistic, often political, forgeries created by computer tools that have lately triggered widespread panic.

Introduced in 2018, the voluntary code will now become a co-regulation scheme, with responsibility shared between the regulators and signatories to the code. In its crackdown against fake news, the European Commission is expected to publish the updated code of practice on disinformation on Thursday.

“Relevant signatories will adopt, reinforce and implement clear policies regarding impermissible manipulative behaviors and practices on their services, based on the latest evidence on the conducts and tactics, techniques and procedures (TTPs) employed by malicious actors,” the document said.

The code will also be linked to stringent new EU rules known as the Digital Services Act (DSA) agreed by the 27-country European Union earlier this year which has a section on combating disinformation.

Based on DSA rules, companies that fail to follow the code can face fines of as much as 6% of their global turnover. They will have six months to implement their measures once they have signed up for the code.

Signatories will also have to take measures to counter advertising which contains disinformation and be more transparent about political advertising.

“The DSA provides a legal backbone to the Code of Practice against disinformation – including heavy dissuasive sanctions,” EU industry chief Thierry Breton, who is leading the EU’s crackdown on disinformation, told Reuters in a statement.