Democratic presidential nominee Hillary Clinton said Friday that there is “no erasing” Republican Donald Trump’s promotion of the false “birther” theory that President Obama was not born in the United States, and said Trump owes Obama an apology.

“We know who Donald is. For five years, he has led the birther movement to delegitimize our first black president. His campaign was founded on this outrageous lie,” Clinton said. “There is no erasing it in history.”

She spoke a day after Trump refused to state his current view on Obama’s birthplace and thus his legitimacy as president. But Trump’s campaign said Thursday night that he does believe Obama was born in the United States, and said he deserves credit for putting questions about Obama’s birth to rest.

Speaking to an audience of supportive African-American women in Washington, Clinton angrily denounced the “temerity” of Trump’s campaign to ever make that assertion. She did not directly address the Trump campaign’s further assertion that her own 2008 campaign promoted the same theory, but her current campaign flatly rejected that claim.

“He is feeding into the worst impulses, the bigotry and bias that lurks in our country,” Clinton said.

“Barack Obama was born in America, plain and simple, and Donald Trump owes him and the American people an apology.”

The Black Women’s Agenda invited both candidates to address its annual conference, but the group’s president said only Clinton had accepted. Clinton used the address to rattle off a long list of policy promises and sketch what she called a more positive view of the country’s future, but the biggest applause came when she attacked Trump.

“There is no new Donald Trump, there never will be,” Clinton said.

“Donald Trump looks at President Obama after eight years as our president. He still doesn’t see him as an American. Think about how dangerous that is. Imagine a person in the Oval Office who trafficks in conspiracy theories and refuses to let them go, no matter what the facts are. Imagine someone who distorts the truth to fit a very narrow view of the world. Imagine a president who sees someone who doesn’t look like him and doesn’t agree with him and thinks, ‘That person must not be a real American.”

“We cannot become insensitive to what he says and what he stirs up. We can’t just accept this. We’ve got to stand up to it,” Clinton said. “If we don’t, it won’t stop.”