WASHINGTON — President Donald Trump’s housing secretary provoked a firestorm Monday by saying slaves brought from Africa were “immigrants” who dreamed of success for their families in the United States.

Ben Carson, who is black, made the stunning remarks during an address to employees at the Department of Housing and Urban Development (HUD) in Washington.

“That’s what America is about: a land of dreams and opportunity,” said Carson, a retired neurosurgeon who grew up in poverty in Detroit.

“There were other immigrants who came here in the bottom of slave ships, worked even longer, even harder for less,” he said.

“But they too had a dream that one day their sons, daughters, grandsons, granddaughters, great grandsons, great granddaughters might pursue prosperity and happiness in this land.”

The comments provoked an instantaneous backlash.

“Immigrants???” tweeted the NAACP, the nation’s largest civil rights organization aimed at ending racial discrimination.

The remarks were condemned as “tragic, shocking and unacceptable” by the US office of the Anne Frank Center for Mutual Respect, a social justice group named after the Dutch Jewish girl whose diary, written before she was killed in the Holocaust, became a globally respected account of discrimination and hope.

“No, Secretary Carson. Slaves didn’t immigrate to America,” the group’s executive director Steven Goldstein wrote.

“This is as offensive a remark as it gets,” the Center said.

The HUD department pushed back, saying on Twitter that the flurry of US media reports on Carson was “the most cynical interpretation” of his remarks.

“No one honestly believes he equates voluntary immigration with involuntary servitude,” the department added.

It was not the first such controversy for Carson, a former Trump rival for the Republican presidential nomination in 2016 and someone who routinely blasts political correctness.

He once said Joseph, the Biblical figure, built Egypt’s pyramids in order to store grain, and not as tombs for the pharaohs.

The retired neurosurgeon has also drawn criticism before when making comparisons to slavery. In 2013 he branded “Obamacare,” the Affordable Care Act championed by President Barack Obama, “the worst thing that has happened in this nation since slavery.”

Rana Hogarth, a history professor and expert on American slavery at the University of Illinois at Urbana-Champaign, said comparing slaves with immigrants was “inappropriate and wildly inaccurate.” She said immigration “suggests a desire of a person to make the journey.”

“I think that he’s either misinformed or made a mistake,” Hogarth said. “His beginning on Ellis Island tells me there’s a major gap in his knowledge of how we talk about different ways people settled the United States and what circumstances they settled in United States.”

Rebecca Scott, a University of Michigan law and history professor, said slavery in the United States was a “dramatically distinct form of migration,” and that slavery made realizing the American dream much more difficult for captured Africans.

“That people had aspirations for their children regardless of how they were brought to the United States was certainly true,” Scott said. “Their capacity to see their aspirations realized was starkly limited by slavery.”

Carson has been considered a hero and motivational speaker in African-American communities for his accomplishments in medicine, and became a prominent speaker in conservative circles after entering politics.