CHICAGO (CBS) — A movie theater chain with a large footprint in Chicago is now banning face-covering masks and fake weapons inside their movie houses nationwide.

The decision comes after the Colorado movie theater massacre. A total of 12 people were killed and 59 wounded during a midnight showing of “The Dark Knight Rises.”

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“At this time, our show schedules circuit-wide will not change,” AMC said in a statement. “We will not allow any guests into our theaters in costumes that make other guests feel uncomfortable and we will not permit face-covering masks or fake weapons inside our buildings.”

Police said a gunman with a gas mask on and dressed in black shot and killed dozens and dozens of people at a movie complex in Aurora, Colo.

Authorities say the suspect, James Holmes, 24, killed 10 people inside the theater complex and that two others died after they were taken from the scene.

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“If guests wish to exchange or refund any tickets, we will honor our existing policy and do as our guests wish,” AMC said. “We are taking necessary precautions to ensure our guests who wish to enjoy a movie this weekend can do so with as much peace of mind as possible in these circumstances.”

Regal Entertainment Group, which also has movie houses in Chicago, said in a statement: “Moviegoers should expect stricter controls over character attire and accessories at our theaters. We reserve the right to inspect the contents of any backpack, package or bag.”

It has been a tradition, especially at blockbuster franchise movies, like Batman, Harry Potter and Star Wars, for fans to dress up in costume. That apparently has now changed in the wake of the Colorado tragedy earlier Friday.

AMC, which is based in Kansas City, has dozens of movie theaters in the Chicago area. It has over 300 locations nationwide.

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One theater that is not banning costumes is the IMAX auditorium at Chicago’s Navy Pier, CBS 2’s Pamela Jones reports. The theater released a statement assuring guests it is taking safety precautions.