US cable channel HBO says hackers have stolen upcoming programming, as Entertainment Weekly reports the theft included a script for an unaired episode of hit show Game of Thrones.

HBO, a unit of Time-Warner Inc, declined to comment Monday on the specific programming stolen in the hack.

Reuters says it received an e-mail on Sunday from a person claiming to have stolen HBO data, including Game of Thrones.

“As most of you have probably heard by now, there has been a cyber incident directed at the company which has resulted in some stolen proprietary information, including some of our programming,” HBO Chairman Richard Plepler wrote in a message to employees, which the company shared with reporters.

The company declined to comment on reports that yet-to-be-aired episodes and scripts were among the data hacked, citing an “ongoing investigation” by unspecified law enforcement officials.

Entertainment Weekly reported that hackers stole 1.5 terabytes of data and had already posted online un-broadcast episodes of Ballers and Room 104, along with “a script or treatment” for next week’s episode of Game of Thrones.

The show is now in its seventh season and due to wrap up next year.