Fourteen people have reportedly been shot dead at a screening of The Dark Knight Rises.
A masked gunman opened fire as people watched the third instalment of Christopher Nolan's Batman franchise in Aurora, Colorado, at just after midnight today.
According to reports, at least 14 people are dead and more than 50 people have been injured.
The man apparently used tear gas during the incident and also shot a baby. He is thought to have been wearing armour and a gas mask - with some reports suggesting he was dressed as Batman villain Bane from the movie.
According to Denver reporter Justin Joseph of KDVR, the man stood up brandishing a gun as soon as Batman appeared on screen. Movie-goers apparently initially thought it was part of the film.
"As people ran this gunman, or gunmen, opened fire hitting people," British newspaper The Telegraph quotes him as saying. "Police sources have told us there are ten bodies inside the cinema, most of them children or teenagers, and one baby.
"A baby was shot at point blank range, the family were gathered around screaming.
"There were police on scene when it happened and one of the gunmen was captured quickly."
There are unconfirmed reports that two men might have been involved in the incident, with at least one thought to be in police custody.
The injured people are being transported to hospitals at the moment.
"The scene is still very active and we have little information for release at this time," said police spokesperson Cassidee Carlson.
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