A gunman killed at least 10 people and injured many others early Friday at a cinema in Denver showing new Batman movie "The Dark Knight Rises," local media reported.

Witnesses said the gunman wearing a gas mask opened fire and set off a type of smoke or tear gas bomb at the Century Theater in Aurora Mall near Denver.

Local radio KOA said 30 to 40 people were injured and some may have been killed in the shooting.

Police and firefighters were rushing to the mall after the incident.