His death was announced on social media by Trump, who praised the 31-year-old Kirk, the co-founder and CEO of the youth organisation Turning Point USA, as "Great, and even Legendary."
"No one understood or had the Heart of the Youth in the United States of America better than Charlie," Trump posted on his Truth Social account.
The suspected shooter has not been arrested, Orem, Utah, Mayor David Young said. A person who was taken into custody at the university where Kirk was speaking was not the suspect, according to a source.
Videos posted to social media from Utah Valley University show Kirk speaking into a handheld microphone while sitting under a white tent emblazoned with the slogans "The American Comeback" and "Prove Me Wrong."
A single shot rings out and Kirk can be seen reaching up with his right hand as a large volume of blood gushes from the left side of his neck. Stunned spectators are heard gasping and screaming before people start to run away.
A single shot rings out and Kirk can be seen reaching up with his right hand as a large volume of blood gushes from the left side of his neck. Stunned spectators are heard gasping and screaming before people start to run away.
Kirk was speaking at a debate hosted by his nonprofit political organisation. Immediately before the shooting, Kirk was taking questions for an audience member about mass shootings and gun violence.
"Do you know how many transgender Americans have been mass shooters over the last 10 years?" an audience member asked. Kirk responded: "Too many."
The questioner followed up: "Do you know how many mass shooters there have been in America over the last 10 years?"
"Counting or not counting gang violence?" Kirk asked.
Then a single shot rang out.
The event had been met with divided opinions on campus. An online petition calling for university administrators to bar Kirk from appearing received nearly 1,000 signatures.
The university issued a statement last week citing First Amendment rights and affirming its "commitment to free speech, intellectual inquiry, and constructive dialogue."
Trump and a host of Republican and Democratic elected officials decried the shooting and offered prayers for Kirk on social media.
At the White House, staff members, many of them young and admirers of Charlie Kirk, were ashen-faced as news of the shooting spread.
Trump said on social media he had ordered all US flags flown at half-staff until Sunday in Kirk's honour.
The shooting comes amid a spike in political violence in the United States across all parts of the ideological spectrum. The attacks include the assassination of a Minnesota state lawmaker and her husband at their house in June, the firebombing of a Colorado parade to demand Hamas release hostages, and a fire set at the house of Pennsylvania's governor, who is Jewish, in April. The most notorious of these events is the shooting of Trump during a campaign rally last year.
Turning Point was founded in Chicago in 2012 by Kirk, then 18, and William Montgomery.
It enthusiastically backed Trump after he clinched the GOP nomination in 2016. Kirk served as a personal aide to Donald Trump Jr., the president's eldest son, during the general election campaign.
Soon, Kirk was a regular presence on cable TV, where he leaned into the culture wars and heaped praise on Trump.
Kirk had 5.3 million followers on X and hosted a popular podcast and radio program, "The Charlie Kirk Show." He had also recently co-hosted "Fox & Friends" on Fox News.
with AP
