The European Court of Justice ruled on Thursday that Facebook may need to monitor and delete any illegal content globally in a ruling that human rights defenders say raises fears that some countries will use it to silence dissidents.

The ruling means that social media platforms can be forced to delete content that a national court deems illegal in the EU's 28 countries instead of waiting for a request to delete publications as now under EU rules.

The Luxembourg-based EU court said the company and other social media platforms could be forced to comply with requests to delete content worldwide, even in countries where it is not illegal.

"European law does not prevent a service provider such as Facebook from ordering the removal of completely identical content, sometimes equivalent to comments previously declared illegal," the court said in a statement.

Facebook criticized the ruling, saying that monitoring, interpreting and deleting potentially illegal content in a given country was not the responsibility of social media platforms.

"This undermines the long-held principle that no single country has the right to impose its laws on expression on another country. It also opens the door to imposing obligations on Internet service providers to monitor content and then determine whether it is" similar, "the company said. "Equivalent" to content deemed illegal.

"In order to do this properly, national courts must define a very clear definition of the meaning of 'similar' and 'equivalent' in practice. We hope the courts will take a proportionate and measurable approach to avoid affecting freedom of expression."