Facebook outage shows need for more players, said the head of EU antitrust regulation Margrethe Vestager.

Due to the outage, 3.5 billion users were unable to access social media and messaging services - WhatsApp, Instagram and Messenger.

On Monday, many users switched to apps like Twitter and TikTok. Several Facebook employees told Reuters they believed the outage was caused by an internal error in directing internet traffic to the systems.

"We need alternatives and choices in the tech market, and must not rely on a few big players, whoever they are, that's the aim of (the) DMA," Vestager tweeted.

Last year, Vestager proposed a draft regulation known as the Digital Markets Act (DMA), which would lay out a list of rules for Amazon, Apple, Facebook and Google that would, in effect, force them to change their core business model to allow for increased competition.

Legislators and EU countries are now discussing their own proposals, and they need to agree on three drafts before the technical rules go into effect.