ATLANTA (AP) — President Joe Biden said Saturday that he regrets using the term “illegal” during his State of the Union address to describe the suspected killer of Laken Riley, as his all-but-certain 2024 rival Donald Trump blamed Biden for her death at a rally attended by the Georgia nursing student’s family.

Biden expressed remorse in an interview Saturday after facing frustration from some in his party for the use of the term to describe people who arrived or are living in the U.S. illegally. “I shouldn’t have used illegal, it’s undocumented,” he told MSNBC. The term was once common but is far less so today, particularly among Democrats who more fully embraced immigrant rights’ issues during Trump’s presidency.

The death of Riley, a nursing student, has become a rallying cry for Republicans, a tragedy that they say encompasses the Biden administration’s handling of the U.S-Mexico border amid a record surge of immigrants entering the country. An immigrant from Venezuela who entered the U.S. illegally has been arrested and charged with her murder.

Biden's comments came in an interview with MSNBC’s Jonathan Capehart taped in Atlanta, where the president was meeting with small business owners and holding a campaign rally. Across the state in Rome, Georgia, Trump is expected to hammer Biden on the border as well as his mispronunciation of Riley’s name during the State of the Union address, according to excerpts released by his campaign before the speech.

“What Joe Biden has done on our border is a crime against humanity,” Trump was set to say.

Biden used the term Thursday night during an exchange in which the president pressed Republicans in his address to pass a bipartisan border security deal that fell apart after Trump opposed it. U.S. Rep. Marjorie Taylor Greene, a stalwart Trump ally, then shouted at the president to say Riley ’s name, adding she was killed “by an illegal.”

“By an illegal, that’s right,” Biden responded immediately, before appearing to ask how many people are being killed by “legals.”

Speaking to Capehart, Biden said, “Look, when I spoke about the difference between Trump and me, one of the things I talked about in the border was his, the way he talks about vermin, the way he talks about these people polluting the blood. I talked about what I’m not going to do. What I won’t do. I’m not going to treat any, any, any of these people with disrespect.”

Trump campaign senior adviser Chris LaCivita slammed Biden for apologizing for his language and not to Riley’s family.

“He should be apologizing to the family as opposed to apologizing for the word that he used which is an accurate description,” he told reporters before Trump took the stage.

He blasted the response as “tone deaf” and a “pivotal moment” that highlights the candidates’ “two very distinct differences in approach on the border invasion.”

“There’s a clear difference,” he said. “One is sympathetic, coddling, and making excuses. And one wants to put a stop, put an end to it.”

Biden's expression of regret marked a shift from a day earlier, when Biden had hesitated when asked by reporters if he regretted using the term, saying, “well I probably,” before pausing and saying “I don’t” and appearing to start saying the word “regret.”