(Reuters) -Shares of Take-Two Interactive Software Inc tumbled nearly 6% in premarket trading on Monday following a report that a hacker had leaked the early footage of Grand Theft Auto VI, the next installment of the best-selling videogame.

The unprecedented leak included dozens of videos showing robberies, gunplay and open-world driving and was posted on an online message board. Bloomberg News said sources familiar with the game’s development had confirmed the videos were real.

“It’s a PR disaster, possibly sets back production and hurts morale,” Jefferies wrote in a client note, warning the potential leak of the game’s source code could pose a bigger threat.

“If the source code leaks, it could necessitate significant changes under the hood of the game to ensure its stability, and the server integrity of GTA VI Online once it launches.”

The hacker, who also claimed to be the person behind a cyber incident at Uber Technologies Inc last week, had posted a message on the forum about seeking to “negotiate a deal” with Take-Two.

Take-Two and Rockstar, the company’s studio behind the game, did not respond to requests for comment.

An admin for the message board, GTAForums, said Take-Two had asked for the copyrighted material to be taken down.

“Do not share media or links to leaked copyrighted material. Discussion is allowed,” a banner on GTAForums’ home page read.

Gamers and investors have been waiting for years for the release of GTA VI, the development of which was confirmed in February that had led to a more than 7% jump in Take-Two shares.

“Based on what we see, the game is further along than many believe and (the leak) won’t impact game reception/sales,” Jefferies analysts said.

GTA VI is estimated to generate bookings of $3.5 billion at launch and an annual average of $2 billion thereafter, according to BofA Global Research.

(Reporting by Nivedita Balu and Abinaya Vijayaraghavan in Bengaluru; Editing by Devika Syamnath and Anil D’Silva)