Washington (CNN) Rep. Tim Ryan is accusing House Minority Leader Nancy Pelosi of seeking to "further consolidate her power" as he tries to stoke antipathy over her long tenure as the Democratic leader ahead of this week's leadership elections.

Ryan, an Ohio Democrat in his seventh term, is mounting an uphill battle to defeat Pelosi in the Wednesday elections, seizing on the Democrats' disappointing election results and continued status in the House minority to call for changes at the top of his caucus.

While Pelosi remains a prohibitive favorite, she has taken a series of steps aimed at easing House Democratic concerns that rank-and-file members -- particularly those elected in recent elections -- have little influence over the messaging and strategy. So Pelosi has sent two letters to her colleagues laying out a series of changes she'd like to make, including giving more junior members a bigger say at the leadership table.

And on Monday evening after Ryan publicly criticized Pelosi, she sent a third letter, telling her caucus she would bring a freshman Democrat into the leadership ranks while putting off an idea that irked at least one member of the Congressional Black Caucus.

But Ryan said Pelosi's initial changes did not go far enough.

"I am very disappointed in Leader Pelosi's proposed caucus reforms which are seemingly designed to further consolidate her power over the caucus," Ryan said in a Monday statement. "There is a clear desire among our members to democratize the Democratic Caucus by returning more power to our rank and file members."

Pelosi's office declined to respond to Ryan's criticism, but the Monday letter seemed designed to respond to some of her challenger's attacks.

Ryan says Pelosi should change how Democrats select the leadership of the House Democrats' main campaign arm -- the Democratic Congressional Campaign Committee -- to give members more say in influencing the direction of the group. And Ryan is seizing on criticism leveled by Louisiana Rep. Cedric Richmond -- a prominent member of the Congressional Black Caucus -- who privately told his CBC colleagues over the Thanksgiving holiday that some of Pelosi's changes could have "severe unintended consequences that could diminish our power within the Democratic Caucus."

"We must continue our efforts to democratize the caucus and decentralize the power of the Democratic leader so each member of our caucus plays a role in our future path," Ryan said.

Ryan has just seven public endorsements, with the latest from Alcee Hastings of Florida, whose office told CNN Monday he's backing the Ohio Democrat for the job. While Pelosi has said confidently she has the support of two-thirds of the caucus, Ryan's aides said that the race is much closer, especially since a secret ballot election gives members a chance to vote their will without fear of repercussion.

Pelosi has been resistant in the past to diffusing the power of the leadership, but under increasing pressure from members who have pushed for specific changes she announced her support for some proposals to provide more opportunities for more junior members to serve in senior committee posts or newly created leadership positions.

She proposed that the current third-ranking position, called the "assistant leader" position that is now held by South Carolina Democratic Rep. Jim Clyburn, be switched to an elected position awarded to members who have served fewer than three terms.

Pelosi created the job after Democrats lost control of the House in 2010 and gave it to Clyburn, a senior member of the Congressional Black Caucus, who worked as the chief vote counter. Now she says that job should be held by a member who has been in Congress fewer than three terms -- after Clyburn leaves office. After criticism from the CBC members, Pelosi said Monday she would shelve discussion about the proposal to elect an assistant Democratic leader until a later time.

"Since the proposal addressing the Assistant Democratic Leader position is one that does not apply to this Congress, any further discussion should occur through the Committee on Organization, Standard and Review," Pelosi told her colleagues.

Following the 2014 midterms, Pelosi added a position to the leadership team to focus on message development. She tapped New York Democratic Rep. Steve Israel for that job, but she says she wants that post expanded to go to three "co-chairs" and suggests they should be drawn from those who have been in the House for less than 10 years.

On Friday, Pelosi nominated Rep. Hakeem Jeffries of New York, a rising star from the Congressional Black Caucus, Rep. Cheri Bustos from Illinois and Rep. Matt Cartwright from Pennsylvania to be the new co-chairs for this effort in the next Congress.

She also tapped California Democratic Rep. Eric Swalwell, already a close ally of hers who led an effort to reach millennial voters, as a co-chair of the internal group that determines committee assignments for House Democrats.

As a way to boost profiles of younger members on various committees, Pelosi is proposing that each panel add a "vice chair" with the requirement that those be given to members who have served less than four terms in the House.

A senior Democratic aide said the Pelosi proposals were not a final decision made by the minority leader -- and would only serve as a basis of future discussions within the Democratic Caucus.

There was grumbling within the caucus that Pelosi's plans still did not give enough say to freshman members. So on Monday evening, Pelosi also proposed including a freshman in leadership discussions.

Still, Pelosi's move has irked at least one member of the influential CBC. In a letter last week to his colleagues, Richmond said that such proposals could hurt veteran members -- including many in the CBC -- who currently hold just one leadership position. Moreover, he raised concerns over Pelosi's proposal to turn the assistant leader position into an elected leadership spot for a more junior member -- given that it is currently held by Clyburn, the veteran CBC member.

"We must make sure that we do not send the message that, of the top three leaders, the assistant leader bears the blame for the losses," Richmond said.

Ryan seized on that criticism in his statement Monday.

"That is why my proposed reforms would not change this position, but instead add to the current leadership team a new elected position reserved for members with three terms or less," Ryan said.

This story has been updated.