White House budget chief Mick Mulvaney Mick MulvaneyMick Mulvaney to start hedge fund Fauci says positive White House task force reports don't always match what he hears on the ground Bottom line MORE said Tuesday that President Trump won't sign a GOP tax plan if it raises taxes on the middle class.

Mulvaney said during an interview with Fox Business Network's "Cavuto: Coast to Coast" that the White House will make the determination based on its own "numbers," which he didn't specify.

“If our numbers show ... that taxes are going up on the middle class, we’re not going to sign it," Mulvaney told host Neil Cavuto.

"Here at the White House, our principles remain the same," he continued. "We want lower taxes on the middle class, we want it simpler and fairer on the middle class, and we want that low corporate tax rate."

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Mulvaney's remarks come just hours after a Joint Committee on Taxation analysis found that the GOP's current tax plan would raise taxes on a significant portion of the middle class over time, though about 61 percent of Americans would see their taxes drop in the first year of the Republican plan.

Mulvaney, a former South Carolina lawmaker, said that the House is on schedule to vote on the bill before Thanksgiving.

"I do think we’re still on schedule. Go back a couple of weeks to where the House accepted the Senate version of the budget without any amendments, that actually saved us between 10 and 12 days depending on how you want to count. So that helped a lot," Mulvaney said.

"So yeah, I think we’re still on schedule for the House to vote before Thanksgiving, the Senate to vote shortly after that so both Houses pass their separate bills before December," he added.

"That allows the conference committees to start working out those differences before Christmas.”

Several GOP senators, however, have already raised concerns about the bill in the Senate, where Republicans control just 52 seats.

If Democrats remain unified, Republicans can afford just two defections to allow Vice President Pence to cast a tiebreaker vote.