Sen. Bernie Sanders (I-VT) apologized on Thursday to the women who worked on his presidential campaign in 2016 who’ve accused other staffers of sexual harassment and unwanted advances.

“It appears that as part of our campaign there were some women who were harassed or mistreated and I thank them from the bottom of my heart for speaking out,” Sanders said during a press conference about prescription drug prices. “What they experienced was absolutely unacceptable and certainly not what a progressive campaign or any campaign should be about.”

He went on to say that “the allegations that I have heard, that you have heard, speak to unacceptable behavior that must not be tolerated in any campaign or in any workplace.”

The senator additionally reflected on how he thought the campaign could have done better to address these issues in real-time.

“To the women in our campaign who were harassed or mistreated I apologize,” Sanders said. “Our standards, our procedures, our safeguards were clearly inadequate.”

He added that during his 2018 Senate reelection run, his staff actively worked to implement strong sexual-harassment policies.

Sanders’ statement on Thursday came after a Politico report detailing allegations of forcible kissing and other inappropriate harassment by Robert Becker, a staffer who led Sanders’ Iowa operation. It also included the detail that Becker had been named in a $30,000 discrimination settlement, of which Sanders said he was not aware. Becker had reportedly traveled to South Carolina recently to meet with prospective staff for a 2020 bid—though that was not at the direction of the campaign team.

Additionally, The New York Times recently reported about other women sharing allegations from the 2016 campaign as well as well as a group of alumni requesting a meeting to discuss these issues.

During a CNN interview last week, Sanders offered an apology and said he was not aware of any of the allegations at the time.