The labor-aligned Working Families Party in a statement Friday called on Independent Democratic Conference Leader Jeff Klein to step aside from his leadership post as an investigation is conducted into an allegation that he forcibly kissed a former legislative staffer.

“Elected officials must be held to the highest standards of behavior,” the WFP stated. “The allegations made against Senator Klein are serious and credible, and we therefore strongly agree with those who have called for an independent investigation. In addition, we believe Senator Klein’s response attempting to discredit the former employee who accused him was unacceptable. Based on that conduct and the seriousness of the charges, the WFP calls on both the IDC and the Senate to remove him from his leadership posts until the investigation is completed.”

The party has been at odds with Klein and his eight-member conference and critical of the IDC for working with Republicans in narrowly divided Senate. The IDC has been a key bloc of votes in the chamber and formed a coalition government with the GOP for two years that gave Klein the title of Senate co-president.

Klein on Thursday sent a letter to the Joint Commission on Public Ethics asking they conduct an investigation into the allegation by Erica Vladimer, the then-aide who accused him of the sexual misconduct.

Klein on Wednesday in a conference call with reporters said he would not resign as the leader of the IDC, which was founded in 2011.