A top official with the Maine Democratic Party said on Tuesday night that Graham Platner’s team had been trying to “put their thumb on the scale” in the party’s planning for his replacement as the Democratic nominee for Senate, but that he would have “no role” in the selection process.

“We have repeatedly reiterated to Graham Platner’s team that they have no role in determining our U.S. Senate nominee, nor in determining what this process looks like,” Devon Murphy-Anderson, the party’s executive director, said in a video posted on social media.

The short video represented a behind-the-scenes look at an extraordinary breach between the Democratic nominee for Senate and the party, which was among the many groups to call for Mr. Platner to step aside on Monday after he was accused of rape by a woman he had dated.

Mr. Platner said on Monday that he would “reflect on the best path forward,” but he told his campaign team in a private call that he hoped to use his leverage as the existing nominee to influence who replaced him. Mr. Platner is currently set to face Senator Susan Collins, a Republican, in a race seen as central to the battle for the Senate majority.

In the video, Ms. Murphy-Anderson said that “unfortunately, Graham Platner’s team has repeatedly reached out in an attempt to put their thumb on the scale of what this process looks like.”

For now, he remains the Democratic nominee and faces a July 13 deadline to drop out and be replaced on the ballot. Top Democrats have vowed to pull money from the state if Mr. Platner remains, which would all but cede the critical contest to Republicans.

A spokesman for Mr. Platner did not immediately respond to a request for comment on the video by Ms. Murphy-Anderson.

A wave of virtually every major Democrat and Democratic group abandoned Mr. Platner after he was accused of rape on Monday by Jenny Racicot, a woman he had dated. Mr. Platner has denied “any accusation of nonconsensual behavior.”

Those calling for Mr. Platner to step aside as the nominee in Maine have ranged from Senator Chuck Schumer of New York, the minority leader, to Senator Bernie Sanders of Vermont, an early supporter and ideological ally.

Democratic frustration was rising on Tuesday that Mr. Platner continued to stay in the race.

“It is utter perversity and just unconscionable for Platner and his consultants to try to play God right now, instead of just stepping away from the utter disaster that they’ve caused,” Jon Reinish, a Democratic strategist, said.

The Maine Democratic Party is in the middle of discussions about how to proceed if and when Mr. Platner steps aside.

Earlier on Tuesday, Ms. Murphy-Anderson wrote in an email to members of the state committee that “our goal is to move thoughtfully, deliberately, and as quickly as the circumstances allow.”

State law dictates that if Mr. Platner is to be replaced, he must step down by July 13. The law then gives the party until July 27 to choose his replacement. But how, exactly, the party should do that is an open question.

Among the options that have been discussed are a convention toward the end of the month or some type of statewide caucus. A convention would present extra logistical obstacles, including how delegates would be selected.

Some party officials have warned against anything that looks like a repeat of what happened in 2024, when former President Joseph R. Biden Jr. stepped aside and former Vice President Kamala Harris was all but anointed as the Democratic nominee within hours.

“This can’t happen as a party insider backroom deal,” Senator Chris Murphy, Democrat of Connecticut, wrote on X on Tuesday evening. “Voters are sick of the status quo and they need to have a say here — or our party will squander whatever credibility we have left.”

Several Maine Democrats moved swiftly to express interest in replacing Mr. Platner, presuming he steps down, including three who ran for governor this year and lost.

Troy Jackson, a former president of the Maine Senate, filed paperwork with the Federal Election Commission for a Senate exploratory committee. “While I haven’t made any final decisions yet, I’m deeply humbled by the outpouring of support and encouragement I’ve received,” he said in a statement.

Dr. Nirav Shah, a former director of Maine’s public health agency, called for any candidate to agree to a television debate and multiple town halls and called himself “not an establishment politician.”

Shenna Bellows, Maine’s secretary of state, also said she was seriously considering entering the race. “I believe I am uniquely fit to unite Mainers and defeat Susan Collins in just over 100 days,” she said.