Marilyn Manson [ tickets ]'s concert at the Denver-area Red Rocks Amphitheatre was cancelled on Thursday (4/22) after the show's promoter and city officials agreed that going forward with the booking would be inappropriate so soon after this week's tragic events in nearby Littleton, CO.

The event was being promoted by local Jacor Broadcasting station KBPI as their Birthday Bash Concert and was to feature Second Coming and Local H in addition to a headlining performance by Manson. Refunds for the show were immediately being made available.

In a written statement issued Thursday, Jacor VP and General Manager Don Howe said, ''We made the decision to cancel the show as soon as the details unfolded yesterday of the tragic events at Columbine High School.''

Jacor had been strongly urged by the city of Denver to postpone or cancel the show following reports that those involved with the killings were fans of Manson's music. The Red Rocks Amphitheatre is administered by the city.

Howe apologized Thursday for not issuing the cancellation notice earlier, saying, ''Because the show was nearly sold out, we expeditiously tended to the many details involved with the cancellation before we could make this announcement. We are sincerely sorry if our delayed announcement further aggravated the emotions of those already suffering so much.''

Twelve students and one teacher were killed Tuesday (4/20) and another 22 victims were injured when two students reportedly launched a killing spree through suburban Columbine High School, using guns and explosives to attack fellow students before killing themselves, bringing the death toll to fifteen.

The students blamed for the killings were part of a group that called themselves the Trench Coat Mafia. On a web site purportedly maintained by the group, since removed by its Internet provider, references were made to songs by Marilyn Manson and other aggressive musical acts including Rammstein and KMFDM.

On Wednesday, KMFDM's Sascha Konietzko issued a statement decrying the alleged association between the now-defunct act's music and the events in Littleton. ''From the beginning, our music has been a statement against war, oppression, fascism and violence against others,'' said Konietzko.

Manson was expected to issue a statement later Thursday, according to a publicist at his record label.

Police who continue to explore motives in the tragedy have not named Manson's music or that of any other act as a contributing factor in the killings.

CitySearch Denver has produced a resource guide for area residents to access a complete list of event cancellations, news updates, counseling services and blood donation centers.