Charlie Kirk, a right-wing youth organizer and prominent ally of U.S. President Donald Trump, has died after being shot in the neck while speaking at Utah Valley University on Wednesday, Mr. Trump said.

Video of the attack showed Mr. Kirk, 31, wearing a white T-shirt emblazoned with the word “freedom,” sitting under a tent and speaking into a handheld microphone to a large, outdoor audience. A gunshot rang out and blood poured from the left side of Mr. Kirk’s neck, as he reached up with his right hand. Audience members were seen screaming and running from the scene.

Mr. Trump, who initially called on Truth Social for his followers to pray for Mr. Kirk, posted again an hour later to say that Mr. Kirk had died.

“The Great, and even Legendary, Charlie Kirk, is dead. No one understood or had the Heart of the Youth in the United States of America better than Charlie. He was loved and admired by ALL, especially me, and now, he is no longer with us. Melania and my Sympathies go out to his beautiful wife Erika, and family. Charlie, we love you!” the President wrote.