Toyota Motor on Tuesday halted operations at all of its plants in Japan after a major supplier was hit by a cyberattack, disrupting the automaker's parts supply management system.  The company is suspending 28 lines at 14 plants. Subsidiaries Hino Motors and Daihatsu Motor will also halt operations at some plants in Japan on Tuesday.

The cyberattack hit Kojima Industries, which supplies plastic parts to Toyota. Kojima announced on Tuesday morning that it has received a message demanding ransom and that it has confirmed the existence of a virus.

On Monday, an official close to Kojima Industries told Nikkei: "It is true that we have been hit by some kind of cyberattack. We are still confirming the damage and we are hurrying to respond, with the top priority of resuming Toyota's production system as soon as possible."

Many of the roughly 400 tier 1 suppliers that Toyota deals with directly are connected to the automaker's kanban just-in-time production control system, which allowed the problems at Kojima Industries to spill over to Toyota. The automaker halted production to prevent longer-term damage, and prioritized inspection and recovery of the system.