Earlier this week, Epic Games announced the PUBG-inspired, battle royale variant of Fortnite, its long-in-development sandbox survival game, would be released for free on consoles and PC next week. This development isn’t sitting well with the team at Bluehole, the developers of Playerunknown’s Battlegrounds, who use Epic’s Unreal Engine to power the early access megahit. A press release issued by Bluehole this morning suggests the team is contemplating “further action.”

“We’ve had an ongoing relationship with Epic Games throughout PUBG’s development as they are the creators of UE4, the engine we licensed for the game,” Bluehole’s Chang Han Kim said in the press release. “After listening to the growing feedback from our community and reviewing the gameplay for ourselves, we are concerned that Fortnite may be replicating the experience for which PUBG is known.

“We have also noticed that Epic Games references PUBG in the promotion of Fortnite to their community and in communications with the press,” Chang Han Kim continues. “This was never discussed with us and we don’t feel that it’s right.”

In the announcement trailer for Fortnite: Battle Royale, Epic’s Donald Mustard says, “At Epic, were huge fans of the battle royale genre, and games like PUBG and H1Z1." In the blog post announcing the version, under “The Fortnite Team” byline, Epic writes, “We love Battle Royale games like PUBG and thought Fortnite would make a great foundation for our own version.”

Before Playerunknown’s Battlegrounds was released earlier this year, creator Brendan Greene consulted on H1Z1’s battle royale mode, later spun off as H1Z1: King of the Kill, and cut his teeth creating battle royale mods for military sim ARMA.

The press release cites a Reddit AMA with Greene in which he said in response to a question about other publishers — notably, not Epic — entering the space, “Other companies will, of course, enter the marketplace, but I would just hope they put their own spin on the game mode and not just make a carbon copy!”

Despite that expectation, Chang Han Kim suggests the similarities between the two products are too close for comfort. “The PUBG community has and continues to provide evidence of the many similarities as we contemplate further action.”