The website of Britain's National Crime Agency (NCA) was temporarily taken down on Tuesday in a Distributed Denial of Service (DDoS) attack by hacking group Lizard Squad, a media report said.
The attack was carried out several days after the NCA announced that six teenagers were arrested on suspicion of using a DDoS tool developed by Lizard Squad to target websites, Xinhua reported.
Lizard Squad claimed responsibility for the attack on Twitter.
The arrests were part of a police operation targeting users of Lizard Squad's Lizard Stresser tool, a software that allowed users to pay to take websites offline for up to eight hours at a time, according to a previous NCA statement.
But an NCA spokesman said the DDoS attack wasn't a security breach, and it did not affect the agency's operational capability.
"At worst, it is a temporary inconvenience to users of our website."
In a situation like this, the measures NCA had in place could make sure that its website went back to normal in more or less 30 minutes, the spokesman also said.