The Justice Ministry said Thursday it has shut off its internal computer network's Internet connection after discovering a suspected virus infection in one of the terminals.
While the ministry believes no information has been leaked, it reported the case to police as a possible cyberattack. No confidential information was stored in the computer in question.
The ministry said security software in the system detected a suspicious communication attempt by the computer on May 17. The attempt was blocked by the security software.
The incident comes amid growing concern over cybersecurity in the wake of recent data leaks in Japan, including at the Japan Pension Service overseeing the country's universal pension program.