Frightened students and others at Utah Valley University raced for shelter after a gunman fired a fatal shot at conservative youth activist Charlie Kirk during an outdoor speaking event at the school Wednesday.

President Donald Trump said Kirk was shot and killed as he was speaking at Utah Valley University. Videos posted to social media 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 reaches for his neck. A large volume of blood gushes from the left side of his neck. Stunned spectators gasp and scream.

Utah Gov. Spencer Cox called the killing a “political assassination."

A “person of interest” was in custody Wednesday evening, Cox said, though no charges were immediately announced.

Utah authorities said the shooter wore dark clothing and potentially fired from a roof on campus some distance away.