Massachusetts Sen. Elizabeth Warren attacked former New York City Mayor Mike Bloomberg at the South Carolina Democratic debate Tuesday night over claims he told a pregnant employee to “kill it.”

Warren said she lost a job at 21 due to her pregnancy, then added, “At least I didn’t have a boss who said to me, ‘Kill it,’ the way that Mayor Bloomberg alleged to have said to one of his pregnant employees.”

Bloomberg responded, “I never said that. And for the record, if she was a teacher in New York City, she would never have had that problem. We treated our teachers the right way, and the unions will tell you exactly that.”

“Then let the women have the opportunity to speak,” Warren replied. “They are bound by non-disclosures so that they cannot speak.”

The allegations come from a Washington Post investigation that unearthed several accusations of Bloomberg supporting hostile work environments and sexist comments, including telling one of his employees who was pregnant at the time, Sekiko Sakai Garrison, to “kill it.”