WASHINGTON, July 20: A 24-year-old man – dressed as a Batman – entered a cinema in Colorado early on Friday and opened fire with various weapons, killing at least 12 people and injuring 50.

US Federal officials identified the man as James Holms and said so far there’s no indication it was a terrorism-related incident.

The tragic shooting in a cinema hall in the city of Aurora, Colorado, forced US President Barack Obama to cancel a campaign event and focus on the incident.

“We may never understand what leads anyone to terrorise their fellow human beings, such violence, such evil senselessness is beyond reason,” Mr Obama told a gathering in Fort Myers, Florida, before returning to Washington.

Police said Holms entered the Century Theatre, wearing a bullet-proof vest and a gas mask and opened fire at viewers during the screening of the new Batman film, The Dark Night Rises.

According to eye witnesses, Holmes tossed a tear gas canister before opening fire at viewers, killing 12 and injuring 50, some of whom have been reported in critical condition.

Since some other viewers were also wearing Batman costumes, it confused police and they had problem locating the shooter.

Later, they found him outside at his car, where he told police he had explosives stored somewhere. Police confirmed that they found “buckets of ammunition” and some explosive in his apartment in Aurora.

They also said the apartment was booby-trapped.

Aurora police said at around 12:39am, they received multiple reports of shooting at a theatre complex and the suspect was still shooting at people when they arrived at the scene.

Ten people died at the scene and two others in hospitals, police said, adding that many of the injured were critically injured.

Witnesses told The Denver Post newspaper the suspect entered theatre number 9 through an emergency exit at less than 10 minutes into the film. He then threw some type of explosive and started shooting into the packed room.

The man had a rifle, a handgun and a gas mask when police arrested him. Police have so far not seen evidence of any additional suspects involved in the shooting.