The world's most powerful government shutdown on Saturday after President Donald Trump and the US Congress failed to reach a deal on funding for federal agencies, highlighting America's deep political divisions.
For the first time since October 2013 - when a similar standoff that lasted 16 days kept only essential agency operations running - federal workers were being told to stay at home or in some cases to work without pay until new funding is approved.
Republican and Democratic leaders were expected to renew negotiations on Saturday in the hope of restoring government financing before Monday.
The shutdown began a year to the day after Trump was sworn in as president.
His inability to cut a deal despite having a Republican majority in both houses of Congress marks arguably the most debilitating setback for his administration.
In Twitter posts early on Saturday, Trump blamed Democrat lawmakers.
"This is the One Year Anniversary of my Presidency and the Democrats wanted to give me a nice present," he said.
"Democrats are far more concerned with illegal immigrants than they are with our great military or safety at our dangerous southern border," he said. "They could have easily made a deal but decided to play shutdown politics instead."
Trump said the shutdown showed the need to win more Republican seats in 2018 mid-term elections.
"We can then be even tougher on Crime (and Border), and even better to our Military & Veterans!" he said.
There had been modest hope on Friday when Democratic Senate Leader Chuck Schumer went to the White House to talk with Trump. One person familiar with the events said the two men agreed to seek a grand deal in which Democrats would win protections from deportation for some 700,000 young undocumented immigrants known as "Dreamers" and Trump would get more money for a border wall and tighter security to stem illegal immigration from Mexico.
By early evening, however, that plan was dead. The source said Trump had spoken with conservative Republicans and been hit with their objections to the deal with Schumer.
Last week, Trump rejected a bipartisan Senate deal that would have protected the Dreamers as well as hand the White House $2.7 billion in new money for immigration enforcement at America's borders.
In a statement issued minutes before Friday's midnight deadline for a funding deal, Trump's White House said: "We will not negotiate the status of unlawful immigrants while Democrats hold our lawful citizens hostage over their reckless demands."
The shutdown was cemented when the Senate, meeting late into Friday night, blocked a bill to maintain the federal government's funding through February 16.
The vote was 50-49, well short of the 60 needed in the 100-member chamber to vault the bill over a procedural hurdle.
Four Republicans joined most Democrats in killing the measure. A fifth Republican, Senate Majority Leader Mitch McConnell, voted "no" too, but only as part of a parliamentary manoeuvre to make it easier to bring another bill to the floor.
The breakdown ended a long day of closed-door meetings in Congress and at the White House.