US authorities have launched a manhunt for the suspected killer of young American conservative influencer Charlie Kirk, a loyal ally of President Donald Trump, who was shot dead during a public meeting on a university campus in Utah.

President Trump has already blamed the "radical left" for Kirk's murder, whom he called a "martyr for truth and freedom."

The 31-year-old conservative podcaster, a standard-bearer for pro-Trump youth, was shot in the neck while participating in a meeting of about 3,000 people on the topic of "America's comeback." The killer's motives remain unknown at this time.

"For years, the radical left has compared great Americans like Charlie to Nazis and the worst criminals and mass murderers in the world. This kind of rhetoric is directly responsible for the terrorism we face today in our country, and it must stop immediately," the US president said in a video posted on his social media account Truth Social.

"My administration will find everyone who contributed to this atrocity and any other political violence, including the organizations that finance and support them," he added, quoted by AFP.

Before him, several figures supporting Trump described Charlie Kirk as a "martyr" who died defending conservative and Christian values.

A suspect was arrested but later released the same day, according to the head of the Federal Bureau of Investigation (FBI).

"Our investigation is ongoing," FBI Director Kash Patel wrote on social media.

Charlie Kirk's death was captured on video clips that quickly spread on social media.

According to US authorities, the killer fired from a rooftop about 100 meters from the scene.

The president ordered US flags to be flown at half-mast in tribute to Kirk, who was an important figure in his last presidential campaign.

The huge flag at the White House was lowered.

A fan of debating with students, Charlie Kirk was participating in an outdoor event on the campus of Utah Valley University in the western part of the country.

Around noon local time, "a shot was fired at Charlie Kirk," who was "evacuated from the scene by his bodyguards," the university wrote in X.

Video footage shows him, shot in the neck, collapsing in his chair, while panicked screams can be heard from the audience.

"I want to be clear, this is a political assassination," Utah Republican Governor Spencer Cox said during a press conference.

According to investigators, the single shot was fired from the roof of a building on campus by a man dressed in black in what appears to be a targeted killing.

Former Democratic presidential candidate for the 2024 election, Kamala Harris, said that "political violence has no place in America."

Former President Joe Biden also called for an "immediate end" to this type of violence, echoing other figures on the left: Barack Obama, Bernie Sanders, and California Governor Gavin Newsom.

Other world leaders also spoke out after his murder.

"I am appalled by the murder of Charlie Kirk. There is no excuse for political violence, and every act of it threatens democracy," Canadian Prime Minister Mark Carney wrote on X.

"We must all have the freedom to debate openly and freely, without fear — there is no excuse for political violence," British Prime Minister Keir Starmer said on X.

"A horrific murder, a deep wound to democracy and to those who believe in freedom. I offer my condolences to his family, his loved ones, and the American conservative community," Italian Prime Minister Giorgia Meloni said.

"Charlie Kirk was killed because he spoke the truth and defended freedom. He was a courageous friend of Israel, fought against lies and defended Judeo-Christian civilization," Israeli Prime Minister Benjamin Netanyahu wrote on X.

"I spoke with him just two weeks ago and invited him to Israel. Unfortunately, that visit will not take place," he added.

Sophie Anderson, 45, told the Daily Mail that she was 30 meters from the scene of the incident: "He was shot in the neck and collapsed, immediately gushing blood."

A native of the Chicago suburbs, a Christian and a defender of the right to bear arms, this man had interrupted his studies to devote himself to activism.

He was the leader of a youth movement called Turning Point USA. Founded in 2012 by the then 18-year-old, this association has become the largest group of young conservatives in the United States in the space of a decade.

It includes an army of enthusiastic activists, some of whom were sent by bus to Washington for the January 6, 2021 demonstration that led to the storming of the Capitol.

With 6.9 million followers on Instagram and 3.8 million on YouTube, his influence was widely used by Donald Trump to attract young American men by promoting an ultra-traditional view of the family. | BGNES