Buffalo, New York — President Joe Biden on Tuesday condemned Saturday’s deadly mass shooting in Buffalo as a "racist rampage" and an act of "domestic terrorism," calling on Americans to reject the racist theory that authorities say appeared to have motivated the gunman to carry out the massacre.

"White supremacy is a poison running through our body politic. And it’s been allowed to fester and grow right in front of our eyes," Biden told grieving families during an impassioned speech at a Buffalo community center.

"We need to say as clearly and forcefully as we can that the ideology of white supremacy has no place in America," he added.

"Hate and fear have been given too much oxygen by those who pretend to love America but don't understand America.

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"I call on all Americans to reject the lie and I condemn those who spread the lie for power, political gain and profit. We cannot remain silent."

Officials say the suspected killer, Payton Gendron, allegedly wrote a 180-page document that included references to the racist and antisemitic Great Replacement conspiracy theory, which posits that a cabal of elites are engineering the replacement of whites with non-white immigrants. The18-year-old white man, who lived 200 miles away in Conklin, New York, shot 13 victims, who were almost all Black, at the Tops Friendly Market on Saturday afternoon, killing 10 of them.

He has been arrested and charged in the planned massacre.

Before the speech, Biden and first lady Jill Biden paid their respects at a makeshift memorial across the street from the Tops Friendly Markets store and met with families of the victims as well as first responders.

The first lady placed a bouquet of white flowers at the memorial, which was covered with flowers, signs and candles to honor the victims. New York Gov. Kathy Hochul and Sen. Chuck Schumer, D-N.Y., joined Biden and other local officials at the site.

Biden has repeatedly said that what drove him to run against former President Donald Trump came after a deadly white nationalist rally in Charlottesville, Virginia, in 2017. He was the first president to directly address white supremacy in his inaugural speech.

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In his Buffalo remarks, Biden briefly reflected on his decision to run for president, urging Americans to reject white supremacy and refuse to allow it to "destroy the soul of the nation."

US Attorney General Merrick Garland said authorities are investigating the shooting "as a hate crime and an act of racially motivated violent extremism."

With the nation’s eyes on the east side of Buffalo, residents said the president once again has an opportunity to help families heal and call out racism, white supremacy, and domestic terrorism.

In interviews, community members said they hoped Biden would speak about the level of hatred required to carry out a shooting targeting Black people.