The European Union's top court ruled Thursday that member countries can force Facebook to remove or block unlawful material worldwide, in a case that raises new questions over the responsibilities of tech giants.
The European Court of Justice ruling, which cannot be appealed, is seen as a defeat for Facebook and similar online platforms, as it would increase the onus on them to monitor what appears online.
Internet companies would only be forced to take action worldwide when ordered to do so by a court in EU countries - and not by governments, for example. That means any requests would have to go through a longer procedure than a simple complaint to a regulator.
"EU law does not preclude a host provider such as Facebook from being ordered to remove identical and, in certain circumstances, equivalent comments previously declared to be illegal," the court said. "In addition, EU law does not preclude such an injunction from producing effects worldwide, within the framework of the relevant international law which it is for member states to take into account."
The court ruled after an Austrian politician, Eva Glawischnig-Piesczek, sued Facebook in her home nation to remove a news story that she considered libelous and insulting and could be viewed globally. The user had shared an online news story related to her support for refugees that featured a picture of her.
An Austrian court ruled in favor of Glawischnig-Piesczek, who was the Greens party chair. The country's top court then turned to the EU's top court for an interpretation of a European rule that says online platforms are not liable for illegal content they are unaware of, as long as they act swiftly to remove or block it once they are informed about it.
Facebook said the ruling raises critical questions around freedom of expression.
It already has a system to restrict content if and where it violates any given country's laws. "This ruling goes much further," it said in a statement.
"It undermines the long-standing principle that one country does not have the right to impose its laws on speech on another country," it said.
The move comes after the same court ruled last month that the EU's "right to be forgotten" rules - which allow people to ask for the removal of some search results that come up for their name - do not apply outside the 28-nation bloc.
Thursday's ruling on Facebook is likely to encourage internet platforms more widely to step up their efforts to monitor user content.
The Computer & Communications Industry Association, a lobby group including members such as Amazon, Facebook and Google, said Thursday's decision could infringe the right to free speech.
"The ruling essentially allows one country or region to decide what Internet users around the world can say and what information they can access," said CCIA Europe senior manager Victoria de Posson. "What might be considered defamatory comments about someone in one country will likely be considered constitutional free speech in another. Few hosting platforms, especially startups, will have the resources to implement elaborate monitoring systems."
Activists at the European Digital Rights organization said that companies like Facebook could have to rely on automatic filters that would be unable to distinguish between legal and illegal content. And that would be based on algorithms that the wider public would be unable to evaluate.