by Todd Feurer, CBS Chicago web producer; the Associated Press contributed to this report.By CBS 2 Chicago Staff

CHICAGO (CBS/AP) — Six progressive Chicago aldermen have joined the growing chorus of Democrats calling on Michael Madigan to resign as Illinois House Speaker and Chairman of the Democratic Party of Illinois, over the ComEd bribery scandal, as the utility giant formally pleaded not guilty to bribery charges on Wednesday.

First-term Alds. Daniel LaSpata (1st), Byron Sigcho-Lopez (25th), Rossana Rodriguez Sanchez (33rd), Andre Vasquez (40th), Matt Martin (47th), and Maria Hadden (49th) are the first members of the Chicago City Council to call for Madigan to step down.

READ MORE: No Arrests In Death Of Zion Mother Melanie Yates, Hit By A Stray Bullet

“As progressive leaders on the Chicago City Council, we feel strongly that our current circumstances require a change in leadership. Speaker Madigan’s entanglements in multiple scandals cast a pall of corruption at a time when we must be focused on protecting working families, seniors and students. He should do what is best for the state and step down from his roles as Speaker of the House and Chairman of the Democratic Party of Illinois,” the aldermen said in a statement.

Last month, federal prosecutors announced ComEd had been charged with a years-long bribery scheme involving the company’s arrangement for jobs, contracts, and payments to allies and associates of Illinois House Speaker Michael Madigan.

ComEd formally pleaded not guilty to bribery on Wednesday, despite admitting to attempts to influence state legislation favorable to its business through the bribery scheme.

The plea was largely a formality under a deferred prosecution agreement unsealed last month and doesn’t mean that ComEd is now saying it did nothing wrong. The agreement requires that ComEd admit wrongdoing, pay a $200 million fine and cooperate with investigators in return for dismissal of the charge later.

In the written agreement, ComEd admits to supplying benefits to associates of Madigan — the nation’s longest serving statehouse speaker — from 2011 to 2019 in exchange for the speaker’s help in pushing through legislation favorable to the utility.

ComEd attorney Reid Schar entered the plea on the company’s behalf.

Court proceedings against ComEd are now on hold until 2023, when prosecutors will assess whether it has fully complied with the terms of the deferred prosecution deal.

Madigan was not identified by name in the case, and has not been charged with a crime. The speaker has insisted he has done nothing wrong, and has no intention of stepping down.

In a statement released last week, he repeated his assertion of inculpability and “will continue to lead the effort to defeat Donald Trump” and add Democrats to Capitol Hill and the Statehouse.

READ MORE: It's Music To Chicagoans' Ears: New Christkindlmarket Flute Shaped Mug Now Available

“I understand that the last couple of weeks have been difficult for our caucus and party, and I have had many candid conversations with members of the Democratic caucus on this matter,” Madigan said. “The feedback is positive and demonstrates continued support for me and my leadership roles. I have no plans to resign.”

At least nine Democratic state lawmakers, including six members of the Illinois House, have said Madigan should immediately resign his post.

Democratic state Representatives Kelly Cassidy, of Chicago; Terra Costa Howard, of Glen Ellyn; Yoni Pizer, of Chicago; Stephanie Kifowit, of Oswego, Anne Stava-Murray, of Naperville; and Stephanie  Lindsey LaPointe of Chicago; as well as state Senators Heather Steans, of Chicago; Melinda Bush, of Grayslake; and Iris Martinez, of Chicago, all have called on Madigan to step down from one or both of his posts.

Some other Democratic legislators, as well as Mayor Lori Lightfoot and Gov. JB Pritzker, have stopped short of calling on Madigan to step down immediately, saying only that he should resign if the allegations are true.

Tuesday morning, Lightfoot was asked if Madigan is the leader she wants representing Illinois Democrats as the national party formally nominates Joe Biden for president at the Democratic National Convention later this month.

“I think this is a time where you have to have a serious conversation as Democrats at every level about what we stand for, and I think people are having that conversation, and the latest announcement from members of the Democratic Socialist group of City Council, I think speak to the necessity of that conversation moving forward,” Lightfoot said.

Four of the six aldermen who called for Madigan to resign are Democratic Socialists — LaSpata, Sigcho-Lopez, Rodriguez Sanchez, and Vasquez.

Meantime, Pritzker has said Madigan needs to stand up and answer questions about the ComEd bribery scandal.

“I believe that people who serve the public interest, people who get elected to public office have a duty to be transparent, and to live up to the integrity that’s demanded by the public for their public service,” Pritzker said Friday. “People have serious questions about those things in any public servant that isn’t willing to do that, and I’ve made that clear.”

“I think the speaker has an enormous amount to answer for. There are questions that the public needs to hear the answer to. I do, too, and so that’s what I would start with: questions about exactly what happened here, and what are these allegations that are being made that are somewhat vague, frankly,” he added. “I mean, there’s more information you would need, but in that deal – the deferred prosecution agreement, the DPA, for ComEd – there is obviously reference to the speaker and to people around the speaker. I want to know those connections. I want to understand what it is the speaker was doing. He needs to answer these questions. I think many, many of us have called for that.”

MORE NEWS: Dozens Of Chicago Firefighters, Water Department Workers Sue To Block City's Vaccine Mandate

(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. CBS News and The Associated Press contributed to this report.)

CBS 2 Chicago Staff