Former President Barack Obama on Tuesday described the killing of conservative activist Charlie Kirk as “horrific and a tragedy,” while also warning that political rhetoric from the current administration has fueled division in the country.

Obama delivered his remarks at the Jefferson Educational Society’s 17th annual global summit in Erie, Pennsylvania, one week after Kirk was shot and killed during a Turning Point USA event at Utah Valley University.

“Regardless of where you are on the political spectrum, what happened to Charlie Kirk was horrific and a tragedy,” Obama said.

The former president told the audience he had not known Kirk personally but acknowledged his prominence in national politics. “Obviously I didn’t know Charlie Kirk,” Obama said. “I was generally aware of some of his ideas. I think those ideas were wrong, but that doesn’t negate the fact that what happened was a tragedy and that I mourn for him and his family.”

Obama cautioned that the country faces “a political crisis of the sort that we haven’t seen before,” suggesting that the tone set by the current White House was contributing to the problem.