Prime Minister Shinzo Abe¡¯s official website may have come under cyberattack by the group Anonymous, according to Chief Cabinet Secretary Yoshihide Suga.

An unidentified person who claimed to be a member of the mysterious group said it launched the attack that had made the site inaccessible to Internet users as of Thursday morning.

But police, who are investigating the matter, have yet to confirm who orchestrated the shutdown, Suga told a daily press briefing.

Early Thursday morning, someone claiming to be an Anonymous member posted a message on Twitter that read: ¡°@AbeShinzo Whaling IS NOT Cultural Right! Your website is #TangoDown!¡±

The website was apparently back to normal at about 6 p.m.

The Twitter user then posted several photos of dolphins and whales in an apparent protest against Japan¡¯s fishing practices, which Tokyo claims is being carried out in the name of ¡°scientific research.¡±

Public broadcaster NHK reported later the same day that a technique called DDoS (Distributed Denial of Service) was used in the attack. The technique involves directing massive amounts of data at a website to paralyze it.

On Dec. 1, a short video clip titled ¡°Anonymous Op KillingBay2¡± was posted on YouTube, purportedly from the group or one of its members.

In the video, a person wearing a Guy Fawkes mask ¡ª which fits with Anonymous¡¯ modus operandi ¡ª read what was described as a ¡°last and final warning.¡±

¡°Japan, you will be wise to listen and pay heed. You have blood on your hands and smiles on your faces,¡± the person says. ¡°Make no mistake. Profiting from these creatures is a crime we will avenge,¡± the person adds.

The Japan Times could not confirm whether the Twitter user or the masked man in the video are connected to the cyberattacks against the prime minister¡¯s website, whose URL is .