Police identify the gunman as 24-year-old James Holmes
Twelve people are dead after a masked gunman opened fire during a midnight screening of "The Dark Knight Rises" early Friday morning in Aurora, Colo.
At least 38 people — including children — are injured, according to a report on CNN. The mass killing took place in a movie theater complex in the suburb of Denver.
Earlier reports had said that as many as 14 people were dead and 50 injured.
Police said that the conditions of the injured shooting victims varies, with some suffering very serious wounds.
At a news conference, Aurora Police Chief Dan Oates told reporters that a suspect is in custody. Police identified the suspect as 24-year-old James Holmes (pictured, right) of Aurora. Police said he was carrying a knife, a rifle and a handgun when arrested, and one other gun was recovered from the theater. The gunman was also wearing a bulletproof vest and did not resist arrest.
NBC News is reporting that the suspect told police he had explosives in his house and car. He reportedly gave no motive for the killings.
A spokesperson for the Aurora police department and the Federal Bureau of Investigation did not immediately respond to TheWrap's requests for comment.
A spokeswoman for Warner Bros., the studio behind the Batman sequel, said it was cancelling the film's Paris premiere, an event that was originally scheduled to take place on Friday. Director Christopher Nolan and stars Christian Bale and Anne Hathaway were expected to attend the red carpet event.
"Warner Bros. and the filmmakers are deeply saddened to learn about this shocking incident," the studio said in a statement. "We extend our sincere sympathies to the families and loved ones of the victims at this tragic time."
Witnesses described the scene, saying that the gunman threw a gas cannister across the theater before he started shooting with a rifle, handgun and shotgun.
"I think we were 15 minutes in, and there was a chase scene where there was gunfire on screen," witness Quentin Caldwell told CNN. "And right then out of nowhere on the right side of us we hear a very distinct 'pop pop pop pop.' "
His wife jumped, Caldwell said, but "I kind of sat there, thought it was probably just really good special sound effects."
President Barack Obama canceled a campaign event in Winter Park, Florida after news of the tragedy broke, according to a White House pool report. He is expected make some remarks about the killing during a press conference in Ft. Myers, Florida on Friday morning.
In a statement, the president condemned the shooting, calling on Americans to keep the citizens of Aurora in their thoughts and prayers. He said federal and local law enforcement agents were still responding, and said his administration would work with authorities in the wake of the murders.
"Michelle and I are shocked and saddened by the horrific and tragic shooting in Colorado," President Obama said.
Adding, "We are committed to bringing whoever was responsible to justice, ensuring the safety of our people, and caring for those who have been wounded. As we do when confronted by moments of darkness and challenge, we must now come together as one American family. All of us must have the people of Aurora in our thoughts and prayers as they confront the loss of family, friends, and neighbors, and we must stand together with them in the challenging hours and days to come."
Mitt Romney, who is challenging the president in the upcoming presidential election, said he and his wife Ann were saddened by the "senseless violence."
"We are praying for the families and loved ones of the victims during this time of deep shock and immense grief," Romney said in a statement. "We expect that the person responsible for this terrible crime will be quickly brought to justice."
A witness describes the shooting to ABC News in the video below: