A conservative influencer and key ally of Donald Trump was assassinated while addressing a university in the United States.

Charlie Kirk, the de facto leader of the Maga youth movement, was shot in the throat by a gunman from a nearby building at Utah Valley university while answering a question about mass shootings committed by trans people, according to those in the audience.

Graphic footage posted online showed the moment the 31-year-old founder of Turning Point, who was speaking beneath a gazebo in front of a large crowd in an open-air venue, fell back after a single bullet shot hit him in the neck.

Announcing his death, Mr Trump said Kirk was “loved and admired by ALL, especially me”.

“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 said.

Kirk and his wife Erika have two children together, a daughter, aged three, and a son, one.