For the first time since 9/11, a national tragedy forced Hollywood into crisis-management decisions that upended long-established plans for a high-profile release.

In the hours after a gunman’s rampage at a Colorado movietheater left 12 dead and more than 50 wounded, Warner Bros. canceled international premiere events for “The Dark Knight Rises.” TV spots for the pic on its opening weekend disappeared from the airwaves on Friday as news outlets went wall to wall with coverage of the killings in Aurora, Colo.

And the studio moved swiftly Friday to pull from exhibs and online outlets the trailer for “Gangster Squad,” a period drama that featured a scene in which agents spray machine-gun fire into a crowded movie theater from behind the screen. Given the eerie association created by the Aurora shootings, Warner Bros. has since decided to remove the scene from the film, which opens Sept. 7, and is putting reshoot plans into motion, a source with knowledge of the situation told Variety. Warner Bros. would not comment.

Bizzers in Los Angeles were just waking up to the horrendous news of the slayings at the “Dark Knight” midnight screening when Warner Bros. execs made the call to cancel Friday’s skedded premiere in Paris. By day’s end, the studio had tabled red-carpet events to be held in Mexico and Japan this week. It will still hold screenings in those countries but without appearances by stars Christian Bale, Anne Hathaway and others.

“Due to the tragic events in Aurora, Colo., Warner Bros. Pictures has cancelled the previously scheduled personal appearances by the cast and filmmakers in Mexico and Japan on behalf of ‘The Dark Knight Rises,’?” Warners said. “However, in an effort not to disappoint the dedicated fans of the film, we will proceed with our previously scheduled special screenings for invited guests and promotional winners.”

Domestically, the studio’s carefully plotted marketing campaign for “TDKR” was derailed by violence that helmer Christopher Nolan described as “unbearably savage.” TV spots for the pic were dropped by numerous networks out of viewer-sensitivity concerns. There were reports that Warner Bros. had taken steps to limit some of its TV marketing for the pic, but sources close to the situation in Burbank strongly denied it.

In the frenzy of news coverage of the shooting rampage on Friday morning, some nets proactively decided to pull the spots for the pic that had been set to run. There were conflicting reports as to whether Warner Bros. eventually asked for all blurbs to be pulled for the weekend or whether some nets took the initiative on their own.

Sources at two of the Big Four broadcast nets said the studio made a request to pull “Dark Knight” spots that had been set to run this weekend. However, sources close to the studio insisted that all marketing efforts that were already in place before the shootings would proceed as planned. In most cases, spots that were pulled by the nets will be reskedded to run at a later date.

The loss of millions of dollars in commercials during the pic’s opening weekend reflects how significant an impact the mass shooting will have on the tentpole that had been the cornerstone of Warner Bros.’ summer movie sked. One marketing expert estimated the cost of the film’s TV spots on its opening weekend at $3 million-$5 million.

Warner Bros. wasn’t the only Hollywood outfit to react to the fallout from what’s believed to be the worst act of violence committed in a U.S. movie theater. TV execs sent staffers combing through their program lineups for the coming days in search of movies and TV episodes with scenes that might echo too closely the real-life attack unleashed on Aurora, Colo.

(Cynthia Littleton and Josh L. Dickey contributed to this report.)