“There is no magical pot of funding available to meet this moment,” Shalanda Young, who leads the Office of Management and Budget, wrote in a letter to congressional leaders. “We are out of money — and nearly out of time.”

Ukraine assistance has become a flashpoint on Capitol Hill, with new House Speaker Mike Johnson insisting that additional aid is contingent on immigration policy changes. The White House is seeking over $61 billion for Ukraine aid as part of a roughly $105 billion package that would also include funding for Israel’s war against Hamas, US allies in the Pacific and money to house and process undocumented immigrants along the border with Mexico.

Republicans are hoping the Ukraine funding fight can provide leverage as they seek to tighten access to asylum for those entering the US. But negotiations on a sweeping immigration agreement are yet to yield results, with the Senate expected to depart for the Christmas holiday on Dec. 15.

“It’s going to take the administration coming to the table and recognizing that their policy needs to change,” House Intelligence Committee Chairman Mike Turner, an Ohio Republican, said Sunday on CBS News’s “Face the Nation.” “America overwhelmingly wants the southern border addressed. It represents a national security threat.”

The administration is expected to further brief lawmakers this week on the consequences of not renewing the funding by the end of the year.