T-Mobile U.S. Inc said on Friday hackers had accessed personal data of 5.3 million more wireless customers, widening the extent of a breach that has affected millions of current, former and prospective customers.
The data includes address, date of birth, and phone numbers of customers, the company said, adding that it had no indication that the accessed data contained financial information such as credit card or other payment data.
"Our investigation is ongoing and will continue for some time, but at this point, we are confident that we have closed off the access," the company said in a regulatory filing.
The third-largest U.S. wireless carrier said earlier this week that personal data of more than 40 million former and prospective customers was stolen along with data from 7.8 million existing T-Mobile wireless customers.
However, T-Mobile on Friday revealed it had identified 667,000 more accounts of former customers, whose names, phone numbers, addresses, and dates of birth were accessed by hackers.
T-Mobile also said that the breached data of the additional 5.3 million postpaid users did not include any data on social security numbers or driver's license.
The company's update comes after the U.S. Federal Communications Commission (FCC) said on Wednesday it would investigate the data breach.
The company reiterated that it has no indication that the data contained customer financial information, credit card information, debit or other payment information.
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