Workers could be left without pay in stand-off over funding for Trump's wall
US president Donald Trump and Congress, embroiled in a feud over his proposed US-Mexico border wall, have only days to reach a deal before a partial government shutdown could leave about a quarter of the federal workforce without pay.
Mr Trump has demanded $5bn (€4.4bn) as a down-payment on construction of a huge wall that he argues is the only way to keep illegal immigrants and drugs from crossing into the US.
Democrats and some Republicans argue there are less costly, more effective border controls.
The money Mr Trump wants is only a fraction of the $450bn (€397bn) Congress was poised to approve - before the latest battle over the proposed wall - to fund several agencies which will otherwise run out of money on Friday.
Large swathes of the government already are funded through to next September, including the military and agencies that operate public healthcare, education and veterans' programmes.
Several Republican and Democratic congressional aides last week said there was no apparent progress being made toward resolving the stand-off, after Mr Trump and leading congressional Democrats battled each other in front of TV cameras in the White House Oval Office.
"I am proud to shut down the government for border security," Mr Trump told House of Representatives Democratic leader Nancy Pelosi and Senate Democratic leader Chuck Schumer.
Since then, a senior House Republican aide said his party was "in a pickle" over how to keep the government open.
The aide said Republicans, who control both houses of Congress until January 3, would not be able to muster the 218 votes needed in the House to pass a funding bill if it contains Mr Trump's demand for wall money, which Democrats oppose.
If funds run out on Friday, the Nasa space programme would potentially be unfunded, along with national parks, the US diplomatic corps and agriculture programmes.
Similarly, the Department of Justice and the Department of Homeland Security would be vulnerable to shutdowns, although "essential" employees, such as FBI agents, airport security screeners and border patrol agents, would still report to work.
Their pay cheques, however, would not be issued until the shutdown ends and Congress would have to decide whether to award back pay for them, plus any furloughed workers.
A government in such disarray might not play well for Republicans over the Christmas period, especially if Americans also view images for two weeks of Mr Trump holidaying at his exclusive Florida beach-front mansion.
"After the president's comments, when he said he was going to own the shutdown, that sealed the deal for Democrats. There is absolutely no reason for them to cut a deal with this president," said Jim Manley, a political strategist and former Senate Democratic leadership aide.
With the clock ticking, the House is not even bothering to come to work until tomorrow night.
For now, Democrats are waiting for the White House to signal whether it will engage on legislation that would keep programmes operating, but without money for the wall.
White House adviser Stephen Miller told CBS News' 'Face The Nation' programme on Sunday that the administration would "do whatever is necessary to build the border wall". Asked if that included shutting down the government, he said: "If it comes to it, absolutely."
If not, Mr Manley predicted the government would limp along until January 3, when Democrats take control of the House and Ms Pelosi likely becomes the speaker and promptly advances funding, daring the Republican-led Senate to reject it.