$Alphabet-A(GOOGL.US)$'s Google, $Meta Platforms(FB.US)$'s Facebook, $Amazon(AMZN.US)$ and other large online platforms will have to do more to police content online or face heavy fines under new European Union rules.

The Digital Services Act (DSA), which was agreed by the EU's 27 member states over the weekend, seeks to protect online users, for example by banning advertising aimed at children or ads based on race, religion or political views. Tactics that trick people into giving away sensitive data will also be prohibited, and promoted content will have to be clearly labelled.

Specific measures will be required during a crisis, an addendum to the rules prompted by Russia's invasion of Ukraine.

"The DSA will upgrade the ground-rules for all online services in the EU, European Commission President Ursula von der Leyen said in a statement. "The greater the size, the greater the responsibilities of online platforms."

Big tech companies -- defined as those with more than 45 million users in the EU -- could face fines of up to 6% of their global revenue if they violate the new rules. They also face a yearly fee of up to 0.05% of worldwide earnings to help cover the costs of monitoring their compliance.

Smaller companies will be exempt from many of the regulations. They include the traceability of traders, notification of criminal offenses, transparency requirements, and dispute settlements. Medium-sized companies will have more time to comply.

The new rules come into force in 2024.