PSN Down
The PlayStation Network is operational Tuesday. PSN was down for users in Europe and the U.S., Monday. PlayStation Store Screenshot

The PlayStation Network experienced an unexplained outage Monday, but Sony has restored service for subscribers. Users in Europe and the U.S. were the most affected by the disruption. The Phantom Squad claimed responsibility for the hack -- close to 10 hours after the first reports of PSN being down -- but there has no been confirmation of an attack.

Sony has announced it plans to offer extensions to PlayStation Plus and PlayStation Now users affected by the outage.

Users first reported issues with PSN at 12:49 p.m. EST (9:49 a.m. PST). With PSN down, many individuals could not access the PlayStation Store or play game from their digital library. Players were unable to download game updates with PSN down. PlayStation Now subscribers could not stream games during the outage.

Sony has not identified the reason why PSN was down for the majority of Monday, but service was restored around 10:40 p.m. On Twitter, the Phantom Squad claimed responsibility for PSN being down. The hacker group has been threatening distributed denial of service attacks (DDoS) on PSN and Xbox Live to knock those services offline during the holidays. Phantom Squad claimed it was responsible for Xbox Live being down briefly.

Steam also experienced problems during Christmas after a DDoS attack affected 34,000 users. Players accessing the Steam network on Dec. 25 were able to view user information for other members. Valve explained the attack led to a web cache issue leading to users seeing the incorrect account information. "Valve is currently working with our web caching partner to identify users whose information was served to other users, and will be contacting those affected once they have been identified," Valve said in a statement.

"As no unauthorized actions were allowed on accounts beyond the viewing of cached page information, no additional action is required by users," the company said. Phantom Squad took credit for this DDos attack.

Sony announced it would offer extensions for PlayStation Plus, PlayStation Now and video rentals. In the wake of the week-long Christmas 2014 hack by the Lizard Squad, Sony extended PS Plus subscriptions for five days.