White supremacist ideology is helping fuel domestic terrorism in the United States, the head of Homeland Security said Tuesday.

Acting Secretary Kevin K. McAleenan appeared in Jackson, Mississippi, for a forum about preventing violence against religious groups. The conversation included references to mass shootings, including the recent one that killed 22 people at a Walmart in El Paso .

Authorities in Texas say the white man charged in the shooting told police he was targeting Mexicans.

“The attack in El Paso and the violent white supremacist ideology that inspired it offends us all,” McAleenan said Tuesday. “We must address it with moral clarity, this hate that is domestic terrorism, and it must be resisted together by Americans of all races, ethnicities and faiths.”

Others at the forum described the threat in similar terms.

“Racism is a national security threat,” said Democratic Rep. Sheila Jackson Lee of Texas, a member of the House Homeland Security Committee.

Critics of President Donald Trump contend his language has stoked racial and ethnic divisions. Democratic Rep. Bennie Thompson of Mississippi did not name names but said “the racist, xenophobic language that we hear coming from high places” empowers people “to do crazy things.”

Thompson and Jackson Lee also criticized raids last week in which 680 Hispanic immigrants were arrested at food processing plants in Mississippi , the largest workplace sting in the U.S. in at least a decade.

“Last week’s massive ICE raid will have an enormous long-term effect on the state of Mississippi,” Thompson said. “I do not understand why ICE picked this time, right after the country was healing from the targeted attack on Mexicans, to perform these raids in this community. ICE turned the first day of school, a special day that is to be filled with smiles and happiness, into a fearful memory for many of the children in Mississippi.”

McAleenan told NBC on Sunday that the timing of the raids was “unfortunate,” but the action had been planned for more than a year.

Jackson Lee said Tuesday that racists who target Hispanics or other people of color can be bolstered by the workplace raid.

“They see a brown person and they see the government rounding up and they’re saying, ‘That’s what I should be doing, but I won’t round up. I will kill,'” Jackson Lee said.

McAleenan said that domestic terrorism, whether at houses of worship or other places, “has a broad and expansive impact on American citizens and our national climate.”

“These attacks not only end lives, they also degrade our society and diminish the integrity of our national values,” McAleenan said. “They pull at our civic seams and our diverse country and they challenge citizens’ faith in their government’s ability to protect them. Domestic terrorism jeopardizes both our physical security and our perceptions of security.”