Donald Trump has blamed Democrats for the failure of budget talks that have forced the US government to shut down.
On the first anniversary of his inauguration as US President, hundreds of thousands of federal workers face going without pay and many have been told not to turn up for work.
In a dramatic night in Washington DC, Republican leaders fell short of the 60 votes needed in the Senate to pass a spending bill.
This legislation would have provided a fiscal rescue package to keep funding the government until 16 February.
And so technically, the US government ran out of money at midnight on Friday (5am Saturday, UK-time).
Mr Trump tweeted: "This is the One Year Anniversary of my Presidency and the Democrats wanted to give me a nice present. #DemocratShutdown."
This is the One Year Anniversary of my Presidency and the Democrats wanted to give me a nice present. #DemocratShutdown
— Donald J. Trump (@realDonaldTrump) January 20, 2018
He was forced to cancel his weekend trip to Florida where he was planning to celebrate his first year as president at his Mar-a-Lago resort.
Continuing to point the finger of blame, he tweeted: "Democrats are far more concerned with Illegal Immigrants than they are with our great Military or Safety at our dangerous Southern Border.
"They could have easily made a deal but decided to play Shutdown politics instead."
He added: "For those asking, the Republicans only have 51 votes in the Senate, and they need 60.
"That is why we need to win more Republicans in 2018 Election! We can then be even tougher on Crime (and Border), and even better to our Military & Veterans!"
Republicans are claiming that Democrats are holding the government hostage over demands to protect 700,000 "dreamer" immigrants brought to the country as children and now living in the US illegally.
As the midnight deadline passed, the White House said it would not negotiate with the Democrats on immigration until the end of the shutdown.
White House Press Secretary Sarah Huckabee Sanders said: "We will not negotiate the status of unlawful immigrants while Democrats hold our lawful citizens hostage over their reckless demands.
"When Democrats start paying our armed forces and first responders, we will reopen negotiations on immigration reform."
But Senate Minority Leader Chuck Schumer hit back on Twitter, writing: "This will be called the #TrumpShutdown.
"There is no one who deserves the blame for the position we find ourselves in more than president Trump."
Fellow Democrat Kirsten Gillibrand wrote on Twitter: "Republicans control the White House, the Senate, and the House of Representatives.
"No matter how they spin this shutdown, we know what happened: they abandoned their responsibility."
Instead of protecting Dreamers, renewing health insurance for millions of children, and tackling the real problems hurting our families, the president and his enablers in Congress have manufactured a government shutdown.
— Kirsten Gillibrand (@SenGillibrand) January 20, 2018
The American Federation of Government Employees estimates about 850,000 workers, out of a total 3.5 million, could be told to stay home without pay until Congress reaches an agreement.
Food inspections, federal law enforcement, airport security checks, and other vital services will continue, as will social security, other federal benefit programmes and military operations.
But most federal workers will not be paid.
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The last US shutdown lasted for 16 days in October 2013, with around 800,000 workers granted leave.
Shortly before the vote, President Trump tweeted that it was "not looking good for our great Military or Safety & Security on the very dangerous Southern Border".