Washington (CNN) 2020 presidential candidate Pete Buttigieg unveiled a policy plan Tuesday to prevent gun violence in the wake of the mass shootings in Dayton, Ohio, and El Paso, Texas, and said he believes President Donald Trump bears "some responsibility" for the rampages.

As part of his plan, the South Bend, Indiana, mayor would increase federal funding to combat hate and violent extremism, boost federal research into gun violence and work with social media companies to stem incendiary rhetoric spread online.

But, Buttigieg says, part of the immediate response could come from Trump, who on Monday called on the nation to condemn racism and white supremacy but did not acknowledge the impact of his own divisive rhetoric.

"It's too late for him to not be a white nationalist and not bear some responsibility for what's happened here," the South Bend, Indiana, mayor told CNN's John Berman Tuesday on "New Day." "But what he could do is refrain from divisive and politicizing rhetoric and focus on making something happen. How about some action?"

Trump is "part of the problem" and is "incapable of bringing people together," Buttigieg said.