Matsuno: Pro-Russian hackers could be behind blocked web sites

Japan's Chief Cabinet Secretary Matsuno Hirokazu says the government is investigating the cause of Tuesday's online service disruptions, including the possibility of a cyberattack by pro-Russian hackers.

The disruptions prevented public access to some Japanese government websites, including the Digital Agency's portal site.

A pro-Russian hacker group called "Killnet" posted a message on social media claiming responsibility for the attack.

Matsuno told reporters on Wednesday morning that access was disrupted to 23 websites run by four ministries and agencies, but services resumed overnight.

He said no leakage of information or other problems have been confirmed so far.

Matsuno noted that pro-Russian hackers may have bombarded the sites with massive amounts of data in what is known as a DDoS attack.

He added the government is prepared to quickly fix any disruptions in its data system.