WASHINGTON — Homeland Security Secretary Kirstjen Nielsen connected Friday’s New Zealand mosque attacks with acts of racist violence in the U.S., calling the perpetrators “domestic terrorists” and saying they’re an increasing concern for her agency.

Nielsen drew a line Monday between the New Zealand attacks, in a which a gunman who espoused hatred of Muslims killed 50 people at two mosques, and three attacks in the U.S. that authorities have blamed on racism or bigotry.

“We, too, have seen the face of such evil with attacks in places such as Charlottesville, Pittsburgh and Charleston,” Nielsen said in a speech at George Washington University.

One counterprotester was killed at a white supremacist rally in Charlottesville, Va., in August 2017. Attacks at a Pittsburgh synagogue in 2018 and a predominantly black church in Charleston, S.C., in 2015 killed 11 and nine people, respectively.

Nielsen’s remarks connecting the New Zealand attack and incidents of racial violence in the U.S. contrasted with the reaction of her boss, President Donald Trump. He told reporters Friday at the White House that he doesn’t consider “white nationalism” to be a growing threat.

“I don’t really,” Trump said. “I think it’s a small group of people that have very, very serious problems. I guess if you look at what happened in New Zealand, perhaps that’s the case.”

He has previously equivocated about violence by American white supremacists. After the Charlottesville incident, he drew public outrage by saying that there were “very fine people on both sides.”

Nielsen on Monday pledged that her department would seek to prevent attacks like the New Zealand incident.

“They are using the same do-it-yourself, mass-murder tactics as we saw with the horrible assault last week in New Zealand against Muslim worshippers,” Nielsen said. “Attacks on peaceful people in their places of worship are abhorrent.”

“We spend more and more of our time talking about domestic terrorism,” she said in an interview.

Nielsen also said that her department is working with private companies to take down extremist content online.