Former President Barack Obama said the assassination of Charlie Kirk was a “horrific” and “evil act” and called all acts of political violence a “threat to all of us” during an interview on Tuesday.

“Regardless of where you are on the political spectrum, what happened to Charlie Kirk was horrific and a tragedy,” Obama said. “The central premise of our democratic system is that we have to be able to disagree, and have sometimes really contentious debates, without resort to violence.”