In 2015, Mr. Scott pleaded guilty to charges of reckless conduct after he encouraged fans at Lollapalooza in Chicago to climb over security barricades and onto the stage. Two years later, Mr. Scott was sued by a fan who said he had become paralyzed after being pushed from a third-story balcony and dragged onstage while the rapper performed in Manhattan.

Soon after the Astroworld concert, Kylie Jenner, Mr. Scott’s girlfriend, posted a response in an Instagram story.

“Travis and I are broken and devastated,” she said, offering condolences to the victims’ loved ones. “I want to make it clear we weren’t aware of any fatalities until the news came out after the show and in no world would have continued filming or performing.”

Observers had criticized the artist and event organizers for not stopping the show sooner once the violence and chaos became evident.

Mr. Scott also posted a video story to his Instagram account.

“I’m honestly just devastated, and I could never imagine anything like this just happening,” Mr. Scott said, rubbing his forehead in a distraught manner. “I’m going to do everything I can to keep you guys updated and just keep you guys informed of what’s going on. Love you all.”