Lucas Jackson/Reuters Sen. Bernie Sanders' (I-Vt.) campaign suggested the DNC and Hillary Clinton's campaign may have committed “serious apparent violations” of campaign finance law.

WASHINGTON -- State Democratic parties are ticked off that Bernie Sanders is characterizing fundraising arrangements they have with Hillary Clinton’s campaign as corrupt.

A joint fundraising committee set up by Clinton's campaign, the Democratic National Committee and 32 state Democratic parties is essential to the survival of state party organizations, said state leaders, including some who said Sanders' complaints may be poisoning his supporters against Democrats.

Sanders' campaign on Monday sent an open letter to the Democratic National Committee “to convey some extremely serious concerns” about the joint fundraising committee. The letter alleged the committee may have committed “serious apparent violations” of campaign finance laws by over-reimbursing the Clinton campaign.

The Sanders campaign told The Washington Post it directed its letter to the DNC, rather than the Federal Election Commission, which would ostensibly investigate such claims, “as a first step.”

Democratic organizations in Ohio and Virginia quickly weighed in on the spat, emphasizing that their fundraising agreements with the DNC and Clinton’s campaign provide vital financial support, since their activities don't tend to generate small-donor enthusiasm like Sanders’ campaign.

Raymond Buckley, chair of New Hampshire’s Democratic Party, posted on Facebook that the joint fundraising committee “should not be used as a political football.”

State parties said joint fundraising agreements like the one Clinton’s campaign has with the DNC help them because the mega-donors Clinton’s campaign can draw are, as Buckley put it, “out of reach of the average state party.”

"Based upon past interviews and this new situation, I've become skeptical of Sen. Sanders' willingness to invest in building the infrastructure that is needed to win down-ballot races,” Rick Palacio, chair of the Colorado Democratic Party, told The Huffington Post.

Palacio said the joint fundraising agreements have allowed his state party to hire organizers and staffers for voter registration and other outreach programs.

“Politics is a team sport and Democratic politics needs to be more of a team right now than ever before, considering we have a minority in both the U.S. House and the Senate and all these legislatures around the country,” Palacio said.

Democrats have complained that while Sanders has his own joint fundraising agreement with the DNC, he hasn't used it, even though the "political revolution" he advocates could only happen if more Democrats were elected to state legislatures and Congress.

“We know all too well just having the White House isn’t enough to effect all of the change we need, especially here in Michigan, where the Republican Party holds unchecked power at the state level,” said Paul Kanan, the Michigan’s Democratic Party's press secretary.

Some state party officials told HuffPost they fear Sanders' supporters won’t be interested in voting for down-ballot Democratic candidates in November if he tarnishes their reputations.

“The victory fund arrangement is all standard procedure for modern campaigns -- Bernie could (and should) be doing this too if he wants to lead Democrats to victory this year,” a spokesman for a battleground state Democratic Party told HuffPost. He asked for anonymity to speak frankly about Sanders’ allegations against Clinton’s campaign and the DNC. “The tone of these attacks is troubling for us long-term because he's using his bully pulpit to turn his supporters against the Democratic Party.”

Both presidential campaigns have tried to capitalize on the scuffle. The Sanders campaign made a fundraising appeal off its letter to the DNC 26 minutes after making the accusations. Clinton’s campaign fired back with two separate fundraising emails, calling the claims “irresponsible and poisonous” and “completely false.”

Clinton’s campaign, which frequently highlights the work of state and local Democrats, suggested the dispute over how the funds for the committee are distributed reflects Sanders’ lack of interest in being the leader of the party. Sanders has said he decided to run as a Democrat to receive media coverage. He did send fundraising emails for three Democratic congressional candidates he has endorsed last week.

“Instead of trying to convince the next generation of progressives that the Democratic Party is corrupt, Senator Sanders should stick to the issues and think about what he can do to help the Party he is seeking to lead,” Clinton campaign manager Robby Mook said in a statement.