(Bloomberg) -- A group of two dozen Republican senators warned President Joe Biden that they won’t support a debt ceiling increase without “structural” changes to US spending, a shot across the bow as the parties stake out their positions.

The 24 Republicans, led by Utah’s Mike Lee, wrote Biden saying they’re flatly opposed to a debt-ceiling increase on its own — a so-called clean hike — and that any change must come with spending reform that shrinks the annual deficit. Any increase must come with cuts equal to or greater than the amount by which the cap is raised, or “meaningful structural reform” in spending, they said. 

“We do not intend to vote for a debt-ceiling increase without structural reforms to address current and future fiscal realities, actually enforce the budget and spending rules on the books, and manage out-of-control government policies,” they wrote in a letter sent Friday and obtained by Bloomberg News.

The letter did not specify the structural changes the Republicans are seeking. Biden has said he’s open to talks on fiscal reform but that any talks should also include what new revenues — taxes — could shrink the budget shortfall.

The warning comes as Biden and House Speaker Kevin McCarthy prepare to meet and with the US in danger of breaching the federal debt ceiling and defaulting on its obligations later this year. McCarthy is seeking spending cuts as a condition of any deal; Biden has said the debt ceiling is not a bargaining chip, and ignored a shouted question Thursday about when he’d meet McCarthy. 

Any debt ceiling deal will require 60 votes in the Senate, where Democrats hold 51 seats. An increase could therefore pass without a majority of the chamber’s Republicans. But the group’s position reflects the thinking of many Republicans in the House, where the party’s razor-thin majority leaves McCarthy under pressure to win spending cuts.

Signatories include members of Republican leadership, including Conference Chairman John Barrasso of Wyoming and Policy Committee Chairman Joni Ernst of Iowa. Senate Minority Leader Mitch McConnell isn’t among the signatories. 

Read more: McConnell Says Debt-Ceiling Solution Hinges on McCarthy, Biden

McConnell has predicted that the two sides will eventually reach a deal. “I think the important thing to remember is America must never default on its debt. It never has and never will,” he said last week.

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