A partial US government shutdown has taken effect after US lawmakers failed to break a budget impasse.
President Donald Trump, who has to sign off on any deal, is insisting at least $5bn (£4bn) be included for his long-promised wall along the Mexican border.
In the absence of a deal, funding for about a quarter of US federal agencies lapsed at midnight (05:00GMT Saturday).
Both the House and Senate are set to be back in session at noon on Saturday (17:00GMT) to try to resolve the issue.
Meanwhile, nine of 15 federal departments, including State, Homeland Security, Transportation, Agriculture and Justice are now partially shutting down.
Hundreds of thousands of federal employees will have to work unpaid or be put on temporary leave. This is the third time US federal funding has lapsed so far this year, although the other two were brief.
What is the row about and how did we get here?
It’s pretty much all about the wall.
On Wednesday, a bilateral deal appeared to have been agreed in the Senate to keep federal agencies open until 8 February. But the agreement did not include funding for Mr Trump’s wall.
Mr Trump then dug his heels in over the issue after criticism from conservative talk show hosts and other allies and insisted that funds for the wall must be included for him to sign the budget off.
The Republican-controlled House then passed a bill on Thursday approving $5.7bn (£4.5bn) of funding for the wall.
Mr Trump is well aware the Democrats are taking control of the House in January and wall funding will then be opposed.
But the other problem for Mr Trump is that he does not have the 60 votes in the 100-seat Senate he needs to get the House budget passed.
No amount of shuttling between party negotiators on Capitol Hill could resolve the issue before the Saturday deadline.
So what happens now?
Well the Democrats appear to be refusing to budge on funding for the wall.
Senate Democratic leader Chuck Schumer said: “President Trump has thrown a temper tantrum and now has us careening towards a ‘Trump shutdown’ over Christmas.”
Mr Trump seems similarly intractable.
In a video address published on his Twitter account shortly before the shutdown began, he said “there is nothing” his Republican party can do about the shutdown and said “we need the Democrats to give us their votes” to resolve it.
The two houses have promised to talk through the weekend to try to resolve the issue.
Some lawmakers were hopeful that there may be a deal involving less money for the wall and more restrictions on it.
But Mr Trump has also suggested Senate majority leader Mitch McConnell should invoke the so-called “nuclear option” to break the impasse.
The option would mean the bill could be approved in the Senate with a simple majority instead of the 60 currently required.
But Mr McConnell has repeatedly refused in the past to invoke such an extreme legislative manoeuvre. A number of Republican senators on Friday also made clear their staunch opposition to the proposal.