Public relations firm Global Situation Room on Thursday sent a cease and desist letter to Polymarket over the prediction market's planned bar pop-up in Washington.

Polymarket has dubbed the bar "The Situation Room," which the consulting firm's attorney said infringes on its trademark, according to the letter obtained by CNBC. The firm said Polymarket's use of the name gives a false impression that Global Situation Room is "somehow connected or associated with Polymarket's services."

"Indeed, there are obvious overlaps in the uses of GLOBAL SITUATION ROOM and THE SITUATION ROOM such as both marks include 'SITUATION ROOM' and allow consumers to monitor and act on global affairs," the letter, written by Shane Delsman, an attorney at Godfrey & Kahn, reads. "In fact, the marks are so similar, Global Situation Room has already witnessed actual confusion in the form of press requests to comment on the opening of the new THE SITUATION ROOM bar."

The firm demanded that Polymarket immediately stop all use of "The Situation Room" in association with its bar pop-up, remove any instances of it from promotional materials and agree that Polymarket will never again use the moniker.

"We have a literal situation room in our office where we do events, so it's clearly an infringement on our trademark," Brett Bruen, CEO of Global Situation Room, said in an interview with CNBC. "We want to make clear to them that this is our trademark territory. We plan to vigorously defend it, and they should consider their use of terms whether it's 'The Situation Room' or something else."

Polymarket did not immediately respond to an inquiry from CNBC on the cease-and-desist letter.

Global Situation Room gave Polymarket until the end of the day Thursday to say it will take corrective action, or the firm warned it would — metaphorically — take things outside.

"If Global Situation Room does not receive a satisfactory and timely response, it is prepared to take all steps necessary to protect its valuable intellectual property rights, without further notice to Polymarket," the letter said.

The bar, which was announced on X earlier this week, is scheduled to open on Friday at an undisclosed location that has piqued curiosity in Washington due to the secrecy. The prediction market billed it as the "world's first bar dedicated to monitoring the situation."

In addition to standard bar fare, the company said it would feature "live X feeds, flight radar, Bloomberg terminals, and Polymarket screens."