At least 20 people were wounded in a shooting early Friday morning at a movie theater in Aurora, Colorado, an area hospital official told CNN.

All of the wounded suffered from gunshot wounds, which ranged from minor to critical, said Jacque Montgomery, a spokeswoman at the University of Colorado Hospital.

"They`re arriving by police, by ambulance. Some are walking in," she said.

Police were responding to a "shooting incident" at the theater, a dispatcher told CNN. The dispatcher did not provide any additional details.

The shooting incident reportedly occurred during an early morning screening of the new Batman movie, "The Dark Knight Rises," witnesses told CNN affiliate KUSA.

"We saw people running around and screaming," a man, who was not identified, told KUSA.

He said there was confusion in the theater when the shooting began because many believed the sound of gunfire was coming from the movie next door.