Former Texas Rep. Beto O'Rourke, one of the two dozen Democrats vying for the party's presidential nomination, drew a direct link between President Trump's divisive rhetoric on immigration and the apparent motives of the young white man suspected of killing at least 20 people in the predominantly Latino border city of El Paso on Saturday.

"President Trump has a lot to do with what happened in El Paso yesterday," O'Rourke, who used to represent El Paso in Congress, said on "Face the Nation" Sunday.

"Anybody who begins their campaign for the presidency by calling Mexican immigrants rapists and criminals; anyone who, as president, describes asylum seekers at the U.S.-Mexico border as an infestation or an invasion or animals; anyone who describes those who do not match the majority of this country as somehow inherently dangerous or defective; sows the kinds of fear, the kind of reaction that we saw in El Paso yesterday," he added.

On Saturday morning, a gunman walked into a Walmart in El Paso and went on a shooting rampage, killing at least 20 people and injuring more than two dozen. Authorities said the suspect, Patrick Crusius, a 21-year-old white man, surrendered to police without incident.

Federal authorities are investigating the massacre as a possible hate crime and scrutinizing an anti-immigrant political manifesto that denounces the large and growing Hispanic population in Texas, two law enforcement sources told CBS News.

Mr. Trump has denounced the shooting as an "act of cowardice," saying there is no way to justify murdering innocent people. But O'Rourke on Sunday accused the president of sanctioning hateful rhetoric that could fuel violent acts like Saturday's shooting.

"The president not only tolerates, but invites the kind of racism and hatred that not only offends us but changes who we are as a country — and produces the kind of violence that we saw in El Paso," he said.

But O'Rourke also said the massacre highlights a pressing nationwide problem that is "larger than" and predates Mr. Trump's rhetoric.

"It's up to all of us to put an end to this racism and make sure that we just don't tolerate our differences but — as we've shown here in El Paso — we embrace them as the very source of our strength and our success," he added. "And, yes, also our safety and our security."

Less than 24 hours after the massacre in El Paso, nine people were killed and more than two dozen were injured in a shooting in the Ohio city of Dayton. The suspect was killed by authorities.