Nicole Gaudiano

USA TODAY

A group led by backers of Hillary Clinton filed three complaints Tuesday with the Federal Election Commission against Sen. Bernie Sanders and two super PACs that support him.

The American Democracy Legal Fund, established by David Brock, charges that Sanders and his campaign repeatedly accepted contributions in excess of the $2,700 legal limit for individuals per election.

Another complaint alleges a Facebook ad encouraging donations after Sanders’ New Hampshire win did not disclose who paid for the communication. Finally, the legal fund accuses the super PAC Progressive Kick of illegally using Sanders’ name and claims that group and the super PAC Nurses National Nurses United for Patient Protection are illegally coordinating with the Sanders campaign.

The Sanders campaign last month described an FEC warning about excessive contributions as “standard” and said the campaign would address the FEC’s questions. On Tuesday, the campaign dismissed the Brock group’s complaint as frivolous and noted it follows Clinton’s chief strategist Joel Benenson call for Sanders to change his negative tone.

"Just one day after the Clinton campaign said we needed to change our tone, the leaders of their coordinated super PAC, which is funded by millions from Wall Street, filed baseless and frivolous complaints with the FEC,” Sanders campaign manager Jeff Weaver said in a statement. “Tells you all you need to know."

The Clinton campaign declined to comment on the complaints.

Brock, founder of the pro-Clinton super PAC Correct the Record, has targeted Sanders throughout the campaign, raising questions about his commitment to the Black Lives Matter movement and his medical records.

MSNBC reports this is the first time ADLF has filed a complaint against a Democrat.

Sanders has long denounced the unlimited money super PACs spend in support of candidates. His lack of affiliation with a super PAC is a distinction he draws with Clinton at his rallies.

Last month in Massachusetts, when Sanders was introduced at a rally by Karen Higgins, co-president of National Nurses United, the campaign said it is not coordinating with or raising money on behalf of the super PAC and highlighted the difference between that PAC and others.

"This is a PAC that is supported by nurses, one of the most respected and admired professions in the country, and to compare nurses to the billionaires and Wall Street special interests who are supporting other candidates is a preposterous stretch," Sanders' spokesman Michael Briggs said after the rally.