Four members of Lulz Security (LulzSec) have pleaded guilty to hacking more than 70 million PSN and Sony Online accounts in 2011, according to GameSpot's sister site CNET UK. Sony’s PlayStation Network was out of operation and inaccessible for three weeks in April 2011.

LulzSec's official logo.

Aged 18 to 26, the four British men faced charges at Southwark Crown Court in London. The group’s main spokesperson, 20-year-old Jake Davis, also ran the LulzSec Twitter account.

Mustafa Al-Bassam (18), Ryan Ackroyd (26), and Ryan Cleary (21) also pleaded guilty. The group was arrested on charges relating to attacks on sites including the CIA and UK crime agencies, and claimed responsibility for being behind the hacking of more than 70 million PSN and Sony Online accounts in 2011.

The PlayStation Network outage occurred in April 2011 and saw Sony bring down its online gaming and retail services for approximately three weeks, costing the company an estimated $171.1 million. The outage occurred shortly after an attack by "hacktivist" group Anonymous, which insisted that its organisation had nothing to do with the extended downtime.

The four LulzSec members will be sentenced next month. The group previously targeted several gaming-related sites, including Minecraft, League of Legends, and Eve Online.