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.