NTT Docomo chief says personal info breached in cyberattack

The compromised data also included bank account numbers and account holders' names, the chief of the major Japanese mobile phone carrier said at a press conference in Tokyo.

The unauthorized access was detected Wednesday, and the company suspended early Thursday its online services, including "My docomo," which allows subscribers to check their usage.

Also among the leaked information were phone numbers and subscription plan details. Former subscribers were also affected. Meanwhile, no credit card information was compromised.

Maeda also said the company plans to pay compensation to affected people, with the scope of recipients to be determined later.

He declined to comment explicitly on whether artificial intelligence agents were used in the cyberattack, saying the company is still investigating the incident.

"I sincerely apologize for causing great inconvenience and concern to our customers and others involved," he said. "We want to strengthen our system to protect customer information."