White House press secretary Karoline Leavitt says public service layoffs are “imminent” and will happen within two days amid a US government shutdown.

US Vice President JD Vance has also foreshadowed the job cuts, warning the Trump administration will have to take “extraordinary measures”.

“If they [Democrats] are so worried about the effect this is having on the American people, and they should be, what they should do is reopen the government. Not complain about how we respond,” he said.

Much of the government’s operations shut down on Wednesday (AEST), hours after the US Senate rejected a short-term spending measure that would have kept it running until November 21.

Deep partisan divisions have prevented Congress and the White House from reaching a funding deal, setting off what could be a long, gruelling standoff that could lead to the loss of thousands of federal jobs.

President Donald Trump, whose campaign to radically reshape the federal government is already on track to push out some 300,000 workers by December, warned a shutdown could clear the path for “irreversible” actions including cutting more jobs and programs.

Independent analysts warn the shutdown could last longer than previous budget-related closures, with Trump and White House officials threatening to punish Democrats with cuts to government programs and the federal payroll.

The longest government shutdown in US history stretched over 35 days during December 2018 and January 2019 during Trump’s first term as US President, in a dispute over border security.

Trump blow

Meanwhile, Trump has suffered a legal blow in his fight to sack Federal Reserve governor Lisa Cook.

The US Supreme Court on Thursday (AEST) said Cook could stay in her role pending arguments to be heard in January .

In creating the US central bank in 1913, Congress passed a law called the Federal Reserve Act that included provisions to shield it from political interference.

Governors can be removed by a president only “for cause”, although the law does not define the term nor establish procedures for removal. It has never been tested in court.

Washington DC judge Jia Cobb ruled on September 9 that Trump’s claims that Cook committed mortgage fraud before taking office, which Cook denies, likely were not sufficient grounds for removal under the Federal Reserve Act.

Cook sued Trump in August after he announced he would remove her.

Cook has said Trump’s claims did not give him the legal authority to remove her and were a pretext to fire her for her monetary policy stance.

“President Trump lawfully removed Lisa Cook for cause from the Federal Reserve Board of Governors. We look forward to ultimate victory after presenting our oral arguments before the Supreme Court in January,” White House spokesman Kush Desai said.

Representatives for Cook did not immediately respond to a request for comment.

In a 2-1 ruling on September 15, the US Court of Appeals for the District of Columbia Circuit denied the Trump administration’s request to put Cobb’s order on hold.

The Supreme Court has, in a series of decisions in recent months, allowed Trump to remove members of federal agencies that Congress had established as independent from direct presidential control, despite similar job protections for those posts.

Those decisions suggest that the court, which has a 6-3 conservative majority, may be ready to jettison a key 1935 precedent that preserved these protections in a case that involved the US Federal Trade Commission.

But in Cook’s case, the court opted to hear arguments first before deciding the Justice Department’s request to similarly remove her on a preliminary basis.

The court, based on the arguments in January, will decide whether Cook can stay in her post or must go while her legal challenge to her firing proceeds in lower courts.

As it stands at this early stage, the justices are not deciding the merits of the challenge.

-with AAP