India-based Reliance Jio is reportedly investigating allegations the personal data of up to 100 million customers was leaked, in what could prove to be a major setback for the country’s newest operator.

First broken by technology website Fonearena.com, a report alleged Reliance Jio’s consumer data had been posted to independent website magicapk.com (which is now showing as suspended).

This was followed by complaints on Twitter the personal information of Jio users had become publicly available on the same site.

The allegations were then verified by press outlets in the country, including The Indian Express newspaper, which said data on the site had accurate results of subscribers’ names, numbers, email addresses, activation dates and region.

Reliance Jio, which launched commercial services in September 2016 and has already added more than 100 million subscribers, hit back to state the data on magicapk was “unauthentic” and its subscriber data was safe.

“We have informed law enforcement agencies about the claims of the website and will follow through to ensure strict action is taken,” a Reliance Jio company representative told Reuters.

In addition to personal information, Indian website MediaNama reported the leak also extended to the customers’ Aadhaar number, but added those particular details were later redacted.

A users’ Aadhaar number is a unique 12-digit identity for each Indian citizen, and stores biometric data in a centralised database.

The Indian government also uses the number to open bank accounts and verify tax returns.

Many subscribers used the Aadhaar number to register for Reliance Jio services.