HBO said Monday its network was victimised by a cyberattack, and media reports said the hack resulted in the leak of a script of the popular series "Games of Thrones" and content from other productions.
A statement by the Time Warner-owned TV group said a "cyber incident" resulted in "the compromise of proprietary information," and that the company had contacted law enforcement and outside cybersecurity firms.
HBO declined to comment on the specific programming stolen in the hack, but several media reports said hackers obtained the script of a new episode of the award-winning fantasy series as well as unaired episodes of two other programmes, "Ballers" and "Room 104."
"Any intrusion of this nature is obviously disruptive, unsettling and disturbing for all of us," HBO chief Richard Plepler said in a memo to staff.
"I can assure you that senior leadership and our extraordinary technology team, along with outside experts, are working round the clock to protect our collective interests. The efforts across multiple departments have been nothing short of herculean."
Entertainment Weekly reported that hackers stole 1.5 terabytes of data and had already posted online unbroadcast episodes of "Ballers" and "Room 104," along with "a script or treatment" for next week's episode of "Game of Thrones."
Some media journalists received emails from an unidentified address boasting of the breach and proposing unaired content from "Game of Thrones."
The show is now in its seventh season and due to wrap up next year.