Russell Simmons: horse carriages like slavery, Holocaust

Hip-hop mogul and animal-rights advocate Russell Simmons is comparing New York's horse-drawn carriages to slavery and the Holocaust.

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

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.

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

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."

WATCH: Go Inside A NYC Horse Carriage Stable