As the deadline approaches to resolve differences that sparked the US government shutdown, the White House will not rule out another closure.
The White House has not ruled out another federal government shutdown, even as it signalled a willingness to obtain funding for US President Donald Trump's proposed border wall by other means.
In appearances on NBC's Meet the Press and Fox News Sunday, acting White House chief of staff Mick Mulvaney said "you absolutely cannot" eliminate the possibility of another shutdown on Friday if a deal is not reached over the wall.
The White House had asked for $US5.7 billion ($A8 billion), a figure rejected by the Democratic-controlled House of Representatives.
The mood among bargainers has soured, according to people familiar with the negotiations.
"You cannot take a shutdown off the table, and you cannot take $5.7 (billion) off the table," Mulvaney told NBC.
"But if you end up someplace in the middle, yeah, then what you probably see is the president say, 'yeah, OK, and I'll go find the money someplace else'."
A congressional deal seemed to stall even after Mulvaney convened a bipartisan group of lawmakers on Friday.
While the two sides seemed close to clinching a deal late last week, significant gaps remained and momentum appears to have slowed.
The White House and many Republicans want to push the amount that would be spent for building physical barriers to $US2 billion ($A2.8 billion) or higher.
Democrats have said they will keep that figure below $US2 billion, with some saying they support perhaps half that.
In addition, Democrats are pushing to reduce the number of apprehended migrants detained by Immigration and Customs Enforcement, a federal agency. Republicans are resisting.
But Mulvaney did signal that the White House would prefer not to have a repeat of the last shutdown.
The process stretched more than a month, left more than 800,000 government workers without pay, forced a postponement of the State of the Union address and sent Trump's poll numbers tumbling.