US President Donald Trump on Wednesday mourned the death of conservative activist Charlie Kirk, calling him a “martyr for truth” and blaming the “radical left” for fostering the climate that led to the killing.

“For years, those on the radical left have compared wonderful Americans like Charlie to Nazis and the world’s worst mass murderers and criminals,” Trump said in a video posted on his Truth Social platform. “This kind of rhetoric is directly responsible for the terrorism we’re seeing in our country today, and it must stop right now.”

Calling Kirk’s death a “dark moment for America,” Trump vowed justice, pledging to pursue not only the shooter but also those who contributed to what he described as an atmosphere of political violence.

“My administration will find each and every one of those who contributed to this atrocity, and to other political violence, including the organizations that fund it and support it,” Trump said.

Kirk — who rose to prominence as the co-founder of Turning Point USA and a vocal Trump ally who mobilized young conservative voters — was fatally shot Wednesday while speaking at an event at Utah Valley University in Orem, Utah.

Video from the scene captured the moment a single shot rang out as Kirk addressed a crowd. He appeared to collapse in his chair before the camera cut away, followed by chaos in the audience.

Investigators said they believe the fatal shot came from a campus rooftop, fired by an assailant dressed in black in what appeared to be a targeted killing. The suspect remains at large.