NEW YORK (CBSNewYork/AP) — Hip-hop mogul and animal-rights advocate Russell Simmons is comparing New York City’s horse-drawn carriages to slavery and the Holocaust.

Simmons spoke Thursday at an event organized by horse carriage opponents.

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The Wall Street Journal reports that he likened horse carriages to slavery, ethnic cleansing and “people who put people in ovens.”

Simmons urged Mayor Bill de Blasio to follow through on his campaign promise to ban the horse carriages.

De Blasio said Simmons’ remarks didn’t bother him.

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The mayor said he feels “very clear about the mission” to ban horse carriages. He said some initiatives take longer to accomplish than others.

Animal-welfare activists and others have long pressed to get rid of the carriage horses. They say Manhattan traffic is no place for a horse.

But hansom cabbies have said they will not stop fighting to protect their livelihood and backers of the industry say the animals are well cared for.

Asked about Simmons’ remarks about slavery and the Holocaust, a mayoral spokeswoman said, “We respectfully disagree with Mr. Simmons’s characterizations of all of the above.”

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