Sony's global PlayStation Network continued to experience problems for a fifth straight day after an attack from outside hackers disrupted the service.
The network outage, which began Wednesday, is affecting more than 70 million users worldwide, who use it to play video games against friends online, stream movies and shop online.
Players can still play games offline, but are unable to challenge others over the Internet, one of the console's key features.
"We sincerely regret that PlayStation Network and Qriocity services have been suspended, and we are working around the clock to bring them both back online," Sony senior director of corporate communications and social media Patrick Seybold said in a posting on the official PlayStation blog late Saturday.
He said the company had to rebuild its systems to strengthen its network infrastructure.
"Though this task is time-consuming, we decided it was worth the time necessary to provide the system with additional security," Seybold said.
No information was given on when users could expect the service to be restored.
Hacker group Anonymous was originally suspected of causing the disruption as it had previously vowed retribution against the Japanese electronics giant after it took legal action two hackers.
However, in a message on its website Friday, entitled "For Once We Didn't Do It," the group denied responsibility, saying that while it was possible that individual hackers had targeted the network, Sony wasn't an official target.
The message went on to accuse Sony of "taking advantage of Anonymous' previous ill-will towards the company to distract users from the fact that the outage is actually an internal problem with the company's servers."
The outage came during a heavy playing week in the United States, with many public schools closed for spring break and an Easter holiday providing an opportunity for an extended weekend, AFP reported.