UPDATE 1: Sony is continuing to work on getting its services back to normal this morning, and has urged anybody who has experienced difficulties with PSN to try it again. We will update with any further information. Original article continues below.
The group Lizard Squad, which has a website based in Russia, tweeted this following in reference to the outages:
PSN Login #offline #LizardSquad
-- Lizard Squad (@LizardPatrol) December 8, 2014
Sony is aware of the issue, has said it is working on it and will keep PlayStation users updated as things change.
PSN update: we are aware of the issues some users are experiencing, and are working to address them. We'll keep you updated.
-- PlayStation (@PlayStation) December 8, 2014
Here's how the PlayStation Store look on Monday morning.