Officials in New York reacted on Friday after a shooting at a midnight showing of The Dark Knight Rises killed 12 in Colorado. The New York City Police Department will be tightening security, the city's police commissioner Ray Kelly said in a statement.

"As a precaution against copycats and to raise the comfort levels among movie patrons in the wake of the horrendous shooting in Colorado, the NYPD is providing coverage at theaters where The Dark Knight Rises is playing in the five boroughs," he said.

The killing, which happened at a midnight showing of the new Batman movie in a suburb of Denver early on Friday, sparked pandemonium when the attacker hurled a gas canister into the auditorium and opened fire on moviegoers.

James Holmes, 24, is seen in this undated handout picture released by The University of Colorado July 20, 2012. Holmes is the suspect in a shooting attack which killed 12 people at a midnight premiere of the new Batman movie in a suburb of Denver early on Friday, according to law enforcement officials. The University of Colorado Denver|Aschutz Medical Campus confirmed that James Holmes was in the process of withdrawing from the University of Colorado Denver's graduate program in neurosciences. [Photo/Agencies]

About 50 others including children were wounded in the attack in a mall in the Aurora suburb, some of whom were treated for the effects of tear gas, hospital officials said.

"This is a horrific event," Aurora Police Chief Dan Oates told a news conference, adding that a suspect was taken into custody in the parking lot behind the theater. He had initially put the death toll at 14, but a spokesman later told NBC the toll had been revised to 12.

Police said the Aurora gunman had appeared at the front of the theater during the movie and released a canister which let out a hissing sound before gunfire erupted.

Dozens of police were at the scene, and the authorities evacuated the area while they checked for any explosive devices. They said there was no evidence of a second gunman.

"Our regular procedure is actually very strict. We have security officers and we have undercovers coming in and out of the building," John Champ, a security staff at AMC 25 Empire theater in Times Square, told China Daily.

In a radio appearance on Friday morning, New York City Mayor Michael Bloomberg also responded to the Colorado shooting, demanding that gun control be a more central issue in the upcoming presidential elections.

"Soothing words are nice," said Bloomberg, who founded the Mayors Against Illegal Guns coalition in 2006. "But maybe it's time the two people who want to be president of the United States stand up and tell us what they're going to do about it, because this is obviously a problem across the country. And everybody always says, ‘Isn't this tragic?'"

Both candidates should offer clear-cut policy proposals, he said.

"There's something more important than getting re-elected," he said. "And that's standing up for what you think is right."

Obama and Romney both released statements on Friday, offering prayers and demanding justice. Neither responded to Bloomberg's comments.

Obama on Friday cut short his two-day campaign swing, saying there can be "other days for politics."

Obama appeared at a campaign stop in Fort Myers, Florida, saying the federal government stands ready to do whatever is necessary to bring justice to whoever responsible for the shooting. He didn't give his usual campaign speech, devoting the whole of his short remarks to the shooting, and made reflections in light of the shooting.

Police spokesman Frank Fania said the suspect was thought to be in his early 20s. 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.

"He did not resist, he did not put up a fight," Fania said.

Police said the suspect's apartment building had been evacuated and police were looking for explosives there after the suspect made statements about explosives in his residence.

Shamecca Davis hugs her son Isaiah Bow, who survived a mass shooting in Denver, Colorado, on Friday, during which a masked gunman shot at least 12 people in a crowded movie theater. [Photo/Agencies]

CNN quoted one witness as saying he saw a "guy slowly making his way up the stairs and firing, picking random people." Another witness said the gunman opened fire during a shoot-out scene in the movie, leading to confusion.

Chandler Brannon, 25, who had been watching the movie with his girlfriend, said that about 20 minutes into the movie he saw a smoke bomb go off and heard what sounded like fireworks.

Xinhua, Reuters and Gong Yan contributed to this story.

kdawson@chinadailyusa.com