Job cuts were underway at the Treasury Department and the US health agency, spokespeople said, but the total extent of the layoffs was not immediately clear.

Roughly 300,000 federal civilian workers will leave their jobs this year due to a downsizing campaign initiated earlier this year by Trump.

“The RIFs have begun,” White House budget director Russell Vought wrote on social media, referring to so-called reductions in force. A spokesperson for the budget office characterised the cuts as “substantial,” without offering further details.

Trump has repeatedly threatened to fire federal workers during the shutdown standoff, in its 10th day on Friday, and has suggested his administration will aim primarily at “Democrat agencies.”

He has ordered the freezing of at least $28 billion in infrastructure funds for New York, California and Illinois — all home to sizable populations of Democratic voters and critics of the administration.

Trump’s Republicans hold majorities in both chambers of Congress, but need at least seven Democratic votes to pass a funding bill in the Senate, where Democrats are holding out for an extension of health-insurance subsidies.

HHS AND TREASURY

Employees across multiple divisions of the Department of Health and Human Services have received layoff notices, communications director Andrew Nixon said.

The 78,000 workers at the sprawling agency manage major health insurance programs, monitor disease outbreaks, fund medical research, and perform a wide range of other health-related duties.

Roughly 41% of the agency’s staff have been ordered not to report to work during the shutdown, while others have been ordered to continue working without pay.

Nixon said the layoffs were targeted at those who had been furloughed but did not provide further details.

“HHS continues to close wasteful and duplicative entities, including those that are at odds with the Trump administration’s Make America Healthy Again agenda,” he said.

Layoffs have also begun at the Treasury Department, according to a spokesperson who spoke on condition of anonymity.

A labour union official, Thomas Huddleston of the American Federation of Government Employees, said in a court filing he had been told the Treasury Department was preparing 1,300 layoff notices.

It was not clear whether those layoffs would hit the tax-collecting Internal Revenue Service, where 46% of the agency’s 78,000 employees were furloughed on Wednesday.

Other government agencies did not immediately respond to requests for comment.

Labour unions representing federal workers have sued to stop the layoffs, saying they would be illegal during a shutdown.

A federal judge is due to hear the case on October 16.

The government is required by law to give workers 60 days’ notice ahead of any layoffs, though that can be shortened to 30 days.