TOKYO — The chief executive of Kobe Steel warned on Thursday that more quality data about the company’s products may have been falsified than has previously been disclosed, suggesting that fallout could widen further from a scandal that has already affected hundreds of companies worldwide.

“We are reviewing data, including from overseas. It is possible that there could be more cases of wrongdoing,” the executive, Hiroya Kawasaki, told reporters. He added, “Trust in our company has fallen to zero.”

Mr. Kawasaki said it could take Kobe Steel two weeks to complete a review of its records to determine the full extent of the data falsification and decide whether any of the improperly certified products it shipped to customers presented a safety hazard. Makers of cars, airplanes and trains use metal from Kobe Steel, making such a safety assessment imperative.

In Japan, where Kobe Steel is based, attention focused on the country’s renowned high-speed rail network. Two railways that operate Shinkansen “bullet trains” — Central Japan Railway and West Japan Railway — said their trains contained aluminum parts sourced from Kobe Steel that did not meet industry standards.