Toyota was forced to suspend production at all 14 of its plants in Japan after a cyberattack wiped out a key parts supplier.
The Tokyo-based automaker did not say if the shutdown, which is expected to result in a loss of production of 13,000 vehicles, will continue beyond Tuesday.
The company's factories in Japan account for about a third of world production.
Japanese Prime Minister Fumio Kishida told reporters on Monday that the government is investigating the incident and Russian involvement.
It's hard to tell if this has anything to do with Russia until thorough checks are made," Kishida said.
A spokesman for Toyota's supplier, Kojima Industries, said the company was the victim of some kind of cyberattack, but did not provide details.
The hack apparently came after U.S. experts and government officials warned that Russia was likely to ramp up cyberattacks against countries that support Ukraine amid Vladimir Putin's brutal invasion.
In recent days, Japan has pledged $100 million in emergency aid to Ukraine and has joined the United States and the European Union in excluding some Russian banks from the SWIFT global payment system. On Monday, the country also said it would impose sanctions on Russia's central bank.
The hack shows how Toyota's "just-in-time" manufacturing system, which involves delivering parts directly to the production line rather than warehousing, can be vulnerable to failure.
In 2020 and 2021, supply chain problems related to the coronavirus slowed down the production of cars around the world, causing the prices of new used cars to skyrocket.
Toyota production in North America was also interrupted earlier in February due to protests from Canadian truckers.
Toyota, listed on the New York Stock Exchange, traded down 1.3% on Monday morning amid broader market declines.
