As President Donald Trump visited the two American cities touched by mass shootings, Sen. Cory Booker (D., N.J.) and former Vice President Joe Biden on Wednesday both accused the president of fueling violence with racist rhetoric.

Speeches from the two would-be challengers created split-screen moments as Trump met privately with victims and first responders in Dayton, Ohio, and El Paso, Texas.

“You reap what you sow,” Booker said Wednesday morning, hours before he was scheduled to appear in Philadelphia.

The “anti-Latino, anti-immigrant” shooting “was sowed by those who spoke the same words the El Paso murderer did: warning of an ‘invasion.’ It was sowed by those who spoke of an ‘infestation’ of disgusting cities, 'rats and rodents’ talking about majority minority communities. … It was sowed from the highest office in our land, where we see in tweets and rhetoric hateful words that ultimately endanger the lives of people in our country.”

Booker spoke in a Charleston, S.C., church where a white supremacist murdered nine black worshipers in 2015.

Both he and Biden warned of rising violence in America driven by racism, accusing the president of failing to denounce such hatred, and of encouraging it.

“It’s not enough to say, ‘I’m not a racist,’” Booker said. “Because there is no neutrality in this fight. You are either an agent of justice or you are contributing to the problem.”

Biden also noted the El Paso killer’s manifesto echoed Trump’s rhetoric about immigrants as “invaders.” He recounted Trump’s equivocation after the 2017 neo-Nazi rally in Charlottesville, Va., tying those comments to the Tree of Life synagogue shooting in Pittsburgh last year.

“With both clear language and in code, this president has fanned the flames of white supremacy in this nation," Biden said in an afternoon speech in Burlington, Iowa. Later, he said: "Our president has aligned himself with the darkest forces in this nation.”

He also brushed aside the president’s Monday speech, in which Trump read a call for unity from a teleprompter. Biden said Trump’s “low energy, vacant-eyed mouthing of the words written for him condemning white supremacists this week, I don’t believe fooled anyone.”

Trump gave a speech Monday calling for healing and denouncing hate. From the start of his presidential campaign in 2015, however, Trump has focused on grievances and warnings that immigrants are a danger. He rejected any ties to the shootings, and in between visits to the two cities Wednesday hit back at Biden on Twitter.

“Watching Sleepy Joe Biden making a speech. Sooo Boring! The LameStream Media will die in the ratings and clicks with this guy. It will be over for them, not to mention the fact that our Country will do poorly with him. It will be one big crash, but at least China will be happy!” he tweeted.

Earlier, as he left for his visits, Trump told reporters: “My critics are political people. They’re trying to make points. In many cases, they’re running for president and they’re very low in the polls.”

Asked if he has contributed to the divisiveness in the country Trump rejected the idea.

“I think my rhetoric brings people together,” he said, before pivoting to his trade fight with China. “Our country is doing incredibly well. China is not doing well.”

Trump has routinely painted immigrants as dangerous, almost exclusively emphasizing those who commit crimes. At an El Paso rally in February he stressed to the crowd how immigration authorities had arrested “criminal aliens” charged or convicted with “4,000 murders, murders, murders, killings, murders.”

Trump’s campaign has also run more than 2,000 Facebook ads featuring the word “invasion” in the last eight months, the Wall Street Journal reported. The shooter in El Paso seized on that same theme in a manifesto posted online shortly before he began killing, warning of a “Hispanic invasion of Texas.”

He wrote that he had such views before Trump took office.

Booker has directly confronted racism throughout his campaign. In a February visit to South Carolina he said the country needs a president who would confront racism, not one “participating in racist statements demeaning and degrading people like we’re seeing now.”

Editor’s note: An earlier version of this article incorrectly stated that 12 people were killed in a church shooting in Charleston, S.C. Nine people perished as a result of injuries suffered during that incident.