(Reuters) - You survived December's much-heralded Mayan apocalypse, but now fear the "zombie apocalypse" and its deadly attacks? Don't worry. It was a fake, the artwork of hackers in Montana.

Hackers infiltrated the emergency broadcast system of local station KRTV in Great Falls, Montana, a CBS affiliate, and issued the zombie alert, the station said on Tuesday.

Viewers were warned of a so-called zombie apocalypse and advised not to tangle with the monstrous creatures, the station said.

Engineers at the station were investigating the incident, which occurred during a Monday afternoon broadcast, said Jon Saunders, vice president of the station's parent company, Cordillera Communications.

Video posted to the Internet shows the transmission interrupted a local broadcast of the Steve Wilkos talk show.

No images flashed across the screen during the hoax. But a male voice told viewers: "Civil authorities in your area have reported that the bodies of the dead are rising from the grave and attacking the living." The voice warned not "to approach or apprehend these bodies as they are extremely dangerous."

Saunders said early reports suggest similar but separate attacks were launched in the past 24 hours against emergency alert systems for TV stations elsewhere, including Michigan.

"It appears to be more widespread than we thought," he said.

The hoax caused several humorous-minded residents in Great Falls to call authorities to inquire if guns were an adequate defense against zombie hordes.

"We didn't get any serious calls on it," Great Falls Police Department spokesman Bill Hunter said.

Local law enforcement has not been asked to investigate the hack into the Montana station, he said. Hunter said it was not immediately clear why hackers had sought to get a rise out of a zombie scare.

"It's been a real chuckle," he said.