Donald Trump's potential running mate J.D. Vance on Saturday said the "rhetoric" of President Joe Biden's reelection campaign had "led directly" to what he called an attempted assassination of the Republican candidate.

"Today is not just some isolated incident," Vance wrote on X. "The central premise of the Biden campaign is that President Donald Trump is an authoritarian fascist who must be stopped at all costs. That rhetoric led directly to President Trump's attempted assassination."

The apparent assassination attempt on Donald Trump involved "multiple shots (fired) toward the stage from an elevated position outside the rally venue," the US Secret Service said Saturday.

"One spectator was killed, two spectators were critically injured," the agency said in a statement, adding the shooter has been killed, without giving further details.