PORTLAND, Maine (AP) — Sen. Bernie Sanders on Tuesday became the latest and most notable lawmaker to pull support for Maine Democratic U.S. Senate nominee Graham Platner following an allegation of sexual assault, adding to a chorus of calls for him to step aside as party leaders scramble to determine the next steps.

Sanders, a Vermont independent who caucuses with Democrats, has long backed Platner in the high-stakes race against Republican Sen. Susan Collins, but he said in a statement that he spoke with the candidate and “in light of these very serious allegations, I have recommended that he step aside.”