THREE-QUARTERS of a million federal workers are likely to be dumped on unpaid leave after the US government shut down at midnight on Wednesday morning.

Congressional Democrats had demanded a reversal of sweeping healthcare cuts in return for approving a Republican budget, but President Donald Trump and Republicans in Congress have refused to compromise.

The president has insisted Democrats will regret confronting him, vowing to do “things that are irreversible, that are bad” in revenge, including permanently firing many furloughed federal workers.

If the US cannot agree a budget, federal spending is paused. Most federal workers are forced onto unpaid leave, while those considered essential, whose jobs involve “protection of life and property,” are expected to continue working, though their pay will not be issued until the shutdown is resolved.

Democrats are demanding funding for healthcare subsidies that are expiring for millions of people under the Affordable Care Act, raising the costs of insurance premiums nationwide.

Republicans have refused to negotiate for now and have encouraged Mr Trump to steer clear of any talks. After the White House meeting, the president posted a cartoonish fake video mocking the Democratic leadership that was widely viewed as unserious and racist.

The AI-edited video showed House of Representatives minority leader Hakeem Jeffries wearing a cartoon sombrero and handlebar moustache as he listened to Senate minority leader Chuck Schumer, in fake audio, say the Democrats needed to provide healthcare to undocumented immigrants because they needed to win new voters, because “nobody likes the Democrats any more because of all our woke trans bullshit.”

Federal shutdowns have been rare in US history but this is the third under Donald Trump, a sign of the increasing polarisation of Washington politics. Unlike previous shutdowns, there is little sign of negotiation, meaning the closure could be protracted and plunge hundreds of thousands of workers, and services tens of millions of people regularly access, into financial crisis.

Mr Trump’s Office of Management and Budget directed federal agencies to draw up plans for the mass firing of workers today, saying the shutdown could be used to advance the government’s plans to shrink federal government overall.