The developer of the science-fiction action game “Cyberpunk 2077” said its internal systems were breached in a cyberattack and has declined to pay a ransom to retrieve compromised data.

CD Projekt SA on Tuesday said an unidentified hacker accessed its internal network and collected certain data belonging to its capital group. The Polish company said that it has begun restoring the data and that its backups remain intact. The compromised systems didn’t contain personal data of its players or users of its services, the company said.

The hacker left a ransom note in CD Projekt’s system, the company said. In the undated note, a copy of which CD Projekt posted on Twitter, the hacker threatened to sell or leak source codes for the company’s popular videogames and internal documents if the company didn’t come to an agreement with the hacker. The hacker gave the company 48 hours to contact them, according to the note.

“We have dumped FULL copies of the source codes from your Perforce server for Cyberpunk 2077, Witcher 3, Gwent and the unreleased version of Witcher 3!!!” the note said. “We have also dumped all of your documents relating to accounting, administration, legal, HR, investor relations and more!”

CD Projekt shares fell about 5% in Warsaw trading. A CD Projekt representative didn’t immediately respond to a request for comment on what means the hacker used to gain access to systems and data.