AT LEAST 10 people have been killed and more than 20 wounded when two gunmen wearing a gas masks and body armour opened fire at a crowded cinema premiere in Denver.
Authorities have confirmed 10 dead and 39 injured in the shooting at at a cinema at a shopping mall in Aurora, Colorado.
Police arrested the alleged gunmen and were searching for another, following chaotic scenes at a midnight showing of The Dark Knight Rises, the latest Batman movie, KDVR, a local Fox affiliate, reported.
Local radio station 850 KOA Radio quoted witnesses as saying that an individual wearing a gas mask opened fire in a theatre at the Aurora Mall.
The attacker then set off what appeared to be a smoke bomb or teargas bomb.
One witness, Hayden Miller, told Denver's 9News he was in an adjoining cinema when he heard "10-20 shots" and "small explosions".
"We heard people screaming," Mr Miller said.
He said a voice then came over the PA system and "told us to get out".
"Everyone was running, screaming," he said.
One suspect was in custody, police said. It was unclear whether other suspects were involved.