Donald Trump says the Republican National Committee isn't honoring its part of a pledge he signed not to run as a third-party candidate.

Trump said at a campaign event Monday that the RNC violated the pledge by giving tickets for Saturday's presidential debate to "special interest people."

"I signed a pledge, but the pledge isn't being honored by the RNC because those tickets were all to special interest people," Trump said. "The RNC does a terrible job."

Trump campaign manager Corey Lewandowski has called on the RNC to stop giving debate tickets to donors and special-interest groups and instead grant them all to voters.

Trump signed the pledge in September vowing not to run as a third-party candidate should he lose the GOP nomination. But the pledge doesn't contain provisions about who the RNC can invite to debates.

Trump said the pledge was a "double-edged pledge," but didn't clarify exactly what he meant by that.

"As far as I'm concerned, they're in default of their pledge," Trump said.