(CNN) Sen. Bernie Sanders' presidential campaign challenged the results of the Iowa caucuses recount just hours after the state's Democratic Party released its results Thursday night.

The recount had been requested by both Sanders' campaign and the campaign of former South Bend, Indiana, Mayor Pete Buttigieg.

In a complaint sent to the Iowa Democratic Party and Democratic National Committee, the Sanders campaign claims the state party violated its own rules by allowing the Buttigieg campaign to partake in the process because they didn't meet the proper requirements.

"[T]he request submitted by the Buttigieg Campaign was deficient because it failed to provide an explanation of how the national delegation could be altered," 18 potential Sanders delegates wrote in the challenge. "Because he did not...[the] request was deficient and should have been denied."

The Iowa Democratic Party reported Thursday that Buttigieg held his lead over Sanders with the most state delegate equivalents after a recount of select caucus sites.

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