Facebook, Instagram and Facebook Messenger are down for a number of users in a global outage.

Users say they are unable to post new messages or like other people’s posts.

A message on Facebook’s login screen reads: “Facebook is down for required maintenance right now, but you should be able to get back on within a few minutes.”

Facebook confirmed about 6 am that the outage is not related to a DDoS attack on the social media platform.

A DDoS attack is a distributed denial-of-service disruption that attempts to interrupt the normal stream of traffic using a network.

Typically DDoS attacks occur when particular infrastructure or the network itself is flooded with a mass of traffic that overwhelms the system.

Twitter has been flooded with comments about login errors on both platforms. Instagram is owned by Facebook.

The problem appears to have started around 4 am (AEDT) today.