uk nca
The website of the U.K. National Criminal Agency was taken down in a cyberattack claimed by hacking group Lizard Squad. In this photo, a sign is seen outside the NCA headquarters in London on Oct 7, 2013. Reuters/Stefan Wermuth

Cyberattackers from the online group Lizard Squad took down the website of the U.K. National Crime Agency (NCA) on Tuesday, apparently to avenge last week's arrest of its members.

The NCA website was temporarily offline on Tuesday morning, four days after six teenagers were released on bail on suspicion of using cyberattack tools from Lizard Squad to target a national newspaper, a school and several gaming companies, and online stores.

While the timing and target of the previous attacks were not revealed by the NCA, an anonymous agency source told Bloomberg that they included Microsoft’s Xbox Live, Sony’s Playstation network, and Amazon.com. The group has also claimed responsibility for an attack on imageboard website 8Chan.

The attack on the NCA website is consistent with the Lizard Squad’s use of distributed denial of service (DDoS) attacks, which disrupt websites with excessive traffic in order to deny access to visitors. An NCA spokesman said the attack was not especially damaging.

“DDoS is a blunt form of attack which takes volume and not skill. It isn’t a security breach, and it doesn’t affect our operational capability,” NCA spokesman Matthew Niizeki said, according to the Guardian.

“At worst it is a temporary inconvenience to users of our website. We have a duty to balance the value of keeping our website accessible with the cost of doing so, especially in the face of a threat which can scale up endlessly.

“The measures we have in place at present mean that our site is generally up and running again within 30 minutes, though occasionally it can take longer. We think that’s proportionate.”

A Lizard Squad-affiliated Twitter account claimed responsibility for the attack in a Tuesday morning post.

“Stressed out” was a reference to the program used by Lizard Squad, known as Lizard Stresser. Last week, the NCA had arrested six people and visited about 50 others believed to have used the Lizard Stresser DDoS tool in exchange for a fee. The attacks were reportedly paid for through Bitcoin.

On the day of the arrests, the same Twitter account said that the group will begin its operations again shortly.

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