Toyota was set to resume operations at all 14 of its assembly plants in Japan on Wednesday, after a computer system failure halted production in the country a day earlier, the world’s top automaker said.

Production was initially to be restarted at 12 plants and 25 lines in Japan, excluding the Miyata plant in Fukuoka Prefecture and at group member Daihatsu Motor’s plant in Kyoto, the company said in a statement late Tuesday. All plants were expected to resume operations from the afternoon onward.

Tuesday's decision to halt all production immediately raised concerns that the stoppage could be due to a cyberattack, though the company said that was unlikely and that an investigation was underway. In late February last year, production lines at the automaker ground to a halt after one of its suppliers of parts was hit by a cyberattack.