Story highlights Sanders said the chairs of two convention committees are active supporters of his rival, Hillary Clinton

Sanders also wants more of a say on the 15-person committee that drafts the party's platform

New York (CNN) Sen. Bernie Sanders is accusing the Democratic National Committee of tilting the party's convention in favor of Hillary Clinton.

The two leaders -- Connecticut Gov. Dannel Malloy, co-chair of the Platform Committee, and former Massachusetts Rep. Barney Frank, the Rules Committee co-chair, are "aggressive attack surrogates" for Clinton. Frank has long battled with Sanders, penning an In a Friday letter to DNC Chairwoman Debbie Wasserman Schultz obtained by CNN, Sanders said the chairs of two convention committees are active supporters of his rival.The two leaders -- Connecticut Gov. Dannel Malloy, co-chair of the Platform Committee, and former Massachusetts Rep. Barney Frank, the Rules Committee co-chair, are "aggressive attack surrogates" for Clinton. Frank has long battled with Sanders, penning an op-ed in Politico last summer titled "Why progressives shouldn't support Bernie."

"I do not, and the millions who have supported our campaign will not, have any confidence that either of them will conduct committee proceeding in an even-handed manner," Sanders wrote in the letter.

Sanders, who has tussled with the DNC several times this election season, said he's also disappointed that Wasserman Schultz selected only three of the more than 40 names he submitted for the standing committees.

"If the process is set up to produce an unfair, one-sided result, we are prepared to mobilize our delegates to force as many votes as necessary to amend the platform and rules on the floor of the convention," Sanders wrote.

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