Government spokesman Hirokazu Matsuno confirmed that it was a "cyberattack", but without giving further details, recalling that an investigation was still underway.
The Toyota supplier in question, Kojima Industries, explained in a press release on Tuesday that it had detected "a threatening message" last Saturday, before discovering that its computer server had been "infected by a virus".
The statement from Kojima Industries was transmitted by Toyota, because the computer system of this supplier of plastic components was still faulty on Tuesday.
According to the daily Nikkei, the cyberattack would have taken the form of a ransomware (ransomware), a malicious software encrypting data and demanding a ransom to be able to recover them.
However, Toyota said separately that it plans to restart production in Japan on Wednesday.
It had decided to suspend it Monday evening for the whole day of Tuesday in its 14 factories in the country, thus affecting the production of around 13,000 vehicles.
“The risk of cyberattacks is increasing at the moment because of the current situation, including in relation to Ukraine,” Mr. Matsuno recalled on Tuesday, calling on Japanese companies to “strengthen their cybersecurity systems”.
The countries that sanctioned Russia for its invasion of Ukraine, including Japan, are on the alert in the face of the perceived high risk of reprisals from Moscow in the form of cyberattacks.
A symbol of Japanese industrial power, Toyota had already been forced several times in recent months to lower its production targets due to disruptions in supply chains and the global shortage of semiconductors.
© 2022 AFP