Some cities and theaters around the country tightened security on Friday in the wake of a deadly shooting inside a Colorado movie house. Here is a partial list of the steps taken:

AMC Theatres

The company said it is reinforcing security procedures with its theater teams. It will not permit guests in costumes that make others uncomfortable, nor will it allow face-covering masks or fake weapons, AMC said in a news release. Though it declined to provide exact details of what it was doing, citing security concerns, the company said it is working with local law enforcement agencies, its landlords and security teams to "ensure we provide the safest environment possible for our guests."

Los Angeles

After the Colorado shooting, Los Angeles police dispatched officers to major venues where "The Dark Knight Rises" was playing. The Aurora, Colorado, theater was screening the new Batman film when the gunman opened fire.

The department said it will increase officers at area theaters and other places where large crowds gather. "Today, and in the immediate future, the LAPD will be providing high-visibility patrol to major theaters in Los Angeles, as well as other sporting events, concerts and crowded venues," police said in a statement.

Dallas

The Dallas Police Department instructed its patrol officers to provide "extra visibility" at public locations, like movie theaters, where large groups of people gather, it said in a release. The department also told them to be extra vigilant at such locations, stressing that police in the Texas city have been trained on what to do in a situation like the one that unfolded in Colorado.

New York City

Police were posted at more than three dozen New York City theaters showing "The Dark Knight Rises." The NYPD said it was not responding to any specific threat; rather, it was hoping to prevent copycats.