WASHINGTON — The US Senate Budget Committee's chairman wants new federal spending cuts to help reduce the country's "endless supply of debt," setting up a Republican-on-Republican clash.

The Congressional Budget Office released a report Monday that concludes the federal deficit will fall to the lowest level of the Obama administration era, $468 billion. Democrats quickly cited that figure, down from $483 billion last year, as evidence President Barack Obama's policies are working.

Many Republicans, however, zeroed in on another CBO finding: America's debt level will rise from $13 trillion today to $21.6 trillion come 2025.

Fiscal conservatives on Capitol Hill, who helped create the environment that spawned sequestration and spending caps, then keep them in place, reacted with calls for even less government spending.

And there's little evidence thus far they're willing to make an exception for military spending, setting up an intraparty skirmish with GOP defense hawks led by Senate Armed Services Committee Chairman Sen. John McCain, R-Ariz.

"The Congressional Budget Office's new figures show our failure to root out wasteful spending and live within our means," Budget Committee Chairman Sen. Mike Enzi, R-Wyo., said in a statement. "This has left us with an endless supply of debt that grows larger by the day.

"A debt this large doesn't come overnight," said Enzi, who has been quiet thus far about his priorities as the panel's new chairman. "We make promises we pay for with gimmicks and IOUs. It will be a challenge, but I want to change that. The habit of spending now and paying later is deeply ingrained."

The statement suggests Enzi and House Budget Committee Chairman Rep. Tom Price, R-Ga., have little interest in raising defense spending caps in their coming 2016 budget resolution.

The chairmen of an independent bipartisan group focused on fiscal matters, the Campaign to Fix the Debt, say CBO's projections "should pour cold water on claims that our debt problems have been solved."

"It's true that our deficits have fallen tremendously from their recession-era highs, but they will soon be rising again," former Senate Budget Committee chairman Judd Gregg, R-N.H., and former Democratic Pennsylvania Gov. Ed Rendell said.

"Our debt is projected to grow faster than the economy," Gregg and Rendell said. "We need a plan to slow the growth of our debt while speeding the growth of our economy."

A leading congressional fiscal hawk, Sen. Jeff Sessions, R-Ala., told CongressWatch recently that if defense hawks push for higher military spending caps, he will insist they justify every requested additional penny.

"We're going to have to go to more than just general rhetoric but specific justifications because it doesn't do any good to have ... the [2011] Budget Control Act if we're not going to adhere to it but [for] a year or two," Sessions said. "I think erosion of that limit requires careful thought."

Sessions' comments offer a glimpse into the coming fight over a 2016 budget resolution between GOP fiscal and military hawks.

Sessions is a senior member of the Senate Budget Committee, where he has helped lead the fight for government spending cuts and deep deficit reduction. He also is an Armed Services Committee member with ties to the US defense sector.

But, at present, he appears more aligned with his party's fiscal hawks.

While McCain and his closest allies are talking about finding a way to give the Defense Department some relief from across-the-board budget cuts, GOP leaders are not talking at all about increasing defense spending.

During a "60 Minutes" interview Sunday evening, Senate Majority Leader Sen. Mitch McConnell, R-Ky., groused about the size of the national debt.

"We've added more debt during the Obama years than all the presidents from George Washington down to George Bush," he said.

In a twist, the fiscal hawks increasingly cite a view expressed over the last five years by retired US Adm. Michael Mullen, a former Joint Chiefs chairman, that the massive federal debt is as the biggest national security issue.

Collectively, comments by both GOP leaders and their Budget point men suggest top Republicans — especially if they lack the votes to secure deeper domestic spending cuts would prefer to keep domestic and defense spending caps in place.

That could leave GOP hawks stuck trying to free up dollars for military priorities from within the Pentagon's annual budget while also seeking a larger-than-requested overseas contingency operations (OCO) budget.

If leadership sides with fiscal hawks, one Republican lobbyist with ties to senior lawmakers says that for the Pentagon and defense sector, "a good year would be buying back some of sequestration by finding savings inside the defense budget."

Twitter: @BennettJohnT