India's Reliance Jio files complaint over unlawful system access: police

The complaint, made on Monday in Navi Mumbai, where Jio is headquartered, would be the telecom firm's first official acknowledgement of a system breach. Jio has so far denied media reports and user accounts of a leak.

Jio, part of conglomerate Reliance Industries Ltd, did not respond to a Reuters request for comment on Wednesday.

Several local news websites reported late on Sunday that names, telephone numbers and email addresses of Jio users were visible on a site called 'Magicapk,' which was subsequently taken down.

Jio however, said its user data was safe and maintained with the highest security, and that the data on the Magicapk website appeared "unauthentic".

News outlets such as Indian Express and MediaNama reported being able to cross-reference and confirm the veracity of the data on numerous Jio customers known to them.

On Tuesday, Reuters reported that police in the western state of Rajasthan detained a man on suspicion of involvement in the breach, which cyber security analysts said could be the first large-scale leak from an Indian telecoms firm.