Landmark Theaters says it will ban costumes from screenings of “Joker” during its theatrical run in response to concern over audience reaction to the film's depiction of mental illness.

The film opens next Friday.

Also banned are face masks, face paints and toy weapons.

The costume ban follows a military warning of a credible threat to moviegoers of a mass shooting.

Christopher Grey, chief of public affairs for the U.S. Army Criminal Investigation Command, told Lawton ABC-affiliate KSWO Fort Sill, Oklahoma, had been notified of the possible mass shooting threat, which was found on the dark web, by the Texas Department of Public Safety.

There was no word on where the shooting might take place. The threat was not specific to military installations.

“I want customers to be comfortable in their surroundings,” CEO and President of Landmark Ted Mundorff told The Hollywood Reporter. Landmark is the largest independent theater chain in the U.S. with 50 locations across the country.

As of Friday morning, Landmark was the only theater chain to announce the costume ban while AMC theaters and Regal Cinemas will only continue the mask, paint and toy bans in response to a growing concern about the “Joker’s” depiction of mental illness and violence.

Those concerns increased Friday after an alleged U.S. Army document began appearing on social media that outlined a potential mass shooting threat on Oct. 4.

Christopher Grey, Chief of Public Affairs for the U.S. Army Criminal Investigation Command, told Lawton ABC-affiliate KSWO the threat outlined is a credible one. He revealed that Fort Sill, Oklahoma, was notified of the possible mass shooting threat by the Texas Department of Public Safety. Soldiers stationed at Fort Sill were then notified of the threat, though it was not clear where the shooting could occur.

CNN reported the Los Angeles Police Department announced increased “visibility” at theaters during the film’s opening weekend.

“The Los Angeles Police Department is aware of public concerns and the historical significance associated with the premiere of ‘The Joker,’” the LAPD wrote in a statement. “While there are no credible threats in the Los Angeles area, the Department will maintain high visibility around movie theaters when it opens. ... Angelenos should remain vigilant and always be aware of your surroundings. As always, if you see something, say something.”

"Joker" opens in theaters nationwide on Oct. 4, 2019.

Joker Poster
"Joker" could be a major awards contender for Warner Bros. Warner Bros.