Japanese game developer Sega, whose Pass network was hacked last week, said user names and passwords of 1.3 million customers were compromised and has been offered help by loosely-knit hackers group LulzSec to destroy its attackers.

Sega became the latest victim of the cyber attack that has grown sharply in recent months. However, no credit card data was stored on the breached server and so the payment information was not compromised, Sega said.

The Sega Pass website had an announcement on its homepage: Hi SEGA Pass is going through some improvements so is currently unavailable for new members to join or existing members to modify their details including resetting passwords. We hope to be back up and running very soon. Thank you for your patience.

The company has already shut down the Sega Pass website temporarily, while it investigates the incident and has reset all passwords.

Until now, Sega has not named the hackers. Lulz Security or LulzSec, which has acknowledged responsibility for the recent hacks into Sony, Nintendo, Bethesda, The Escapist, PBS, Fox.com, the US Senate, the CIA, and a slew of gaming sites including EVE Online, Minecraft and League of Legends websites, said they did not hack Sega and even offered help to prove their innocence.

@Sega - contact us. We want to help you destroy the hackers that attacked you. We love the Dreamcast, these people are going down, LulzSec tweeted.