Democratic Party leaders have rigged the primary debate schedule in favor of front-runner Hillary Clinton, according to two Democratic presidential candidates, Sen. Bernie Sanders, I-Vt., and former Maryland Gov. Martin O'Malley.

"Four debates and only four debates - we are told, not asked - before voters in our earliest states make their decision," O'Malley said Friday evening while addressing Democratic National Committee (DNC) members and leaders at its summer meeting in Minneapolis, according to The Guardian.

"That's all we can afford? Is this how the Democratic Party selects its nominee?" O'Malley asked.

"This is totally unprecedented in our party's history. This sort of rigged process has never been attempted before. Whose decree is it exactly? Where did it come from? To what end? For what purpose? What national or party interest does this decree serve? How does this help us tell the story of the last eight years of Democratic progress?" he said, adding that the New Hampshire debate is "cynically wedged into the high point of the holiday shopping season so as few people watch it as possible," according to The New York Times.

"We are the Democratic Party, not the undemocratic party!" he exclaimed.

The DNC has scheduled only four debates before people in the early-primary states cast their votes, and six total during the entire election cycle. O'Malley said that such limitations will allow the rhetoric of Republican candidates to go largely unchallenged.

He told reporters after the meeting that he believes the DNC is intentionally rigging the debate process to help Clinton win the nomination, according to Fox News.

When Sanders was asked after the meeting if he agrees with O'Malley's assertion that the primary process is "rigged," Sanders responded, "I do," reported The Hill.

DNC spokeswoman Holly Shulman defended the debate schedule, saying in a statement that it will "give plenty of opportunity for the candidates to be seen side-by-side," according to The Washington Post.

"I'm sure there will be lots of other forums for the candidates to make their case to voters, and that they will make the most out of every opportunity," Shulman said.