The US government has partially shut down after Democrats refused to meet President Donald Trump's demands for five billion dollars to start erecting his Mexican border wall.
Vice President Mike Pence, Mr Trump's son-in-law and senior adviser Jared Kushner and White House budget chief Mick Mulvaney left the Capitol late on Friday after hours of bargaining with congressional leaders produced no apparent compromise.
"We don't have a deal. We're still talking," Senate Appropriations Committee Chairman Richard Shelby told reporters.
Late on Friday, Mr Mulvaney sent agency heads a memorandum telling them to "execute plans for an orderly shutdown".
The gridlock blocks money for nine of 15 Cabinet-level departments and dozens of agencies, including the departments of Homeland Security, Transportation, Interior, Agriculture, State and Justice.
The lack of funds will disrupt many government operations and the routines of 800,000 federal employees.
Roughly 420,000 workers were deemed essential and will work unpaid just days before Christmas, while 380,000 will be given a leave of absence, meaning they will stay home without pay.
Those being given a leave of absence include nearly everyone at Nasa and 52,000 workers at the Internal Revenue Service. About eight in 10 employees of the National Park Service will stay home and many parks were expected to close.
Some agencies, including the Pentagon and the departments of Veterans Affairs and Health and Human Services, were already funded for the year in agreements reached earlier, and they will operate as usual.
Also still functioning will be the FBI, the Border Patrol and the Coast Guard. Transportation Security Administration officers will continue to staff airport checkpoints and air traffic controllers will also remain at work.
'A temper tantrum'
President Trump has openly savoured a shutdown over the wall for months, saying last week he would be "proud" to have one and saying on Friday he was "totally prepared for a very long" closure.
A joint statement by House Minority Leader Nancy Pelosi and Senate Minority Leader Chuck Schumer said: "Instead of honouring his responsibility to the American people, President Trump threw a temper tantrum and convinced House Republicans to push our nation into a destructive Trump Shutdown in the middle of the holiday season."
Early this week, the Senate approved a bipartisan deal keeping government open into February and providing 1.3 billion dollars (£1.03 billion) for border security projects but not the wall.
In a Republican victory on Thursday, the House rebelled and approved a package temporarily financing the government but also providing 5.7 billion dollars (£4.51 billion) for the border wall.
On Friday afternoon, a Senate procedural vote showed that Republicans lacked the 60 votes they would need to force that measure through their chamber.
The White House said Mr Trump did not go to Florida on Friday as planned for the Christmas holiday.