The US State Department formally advised staffers on Thursday, 10 July, that it would be sending layoff notices to some of them soon, coming as part of dramatic changes to the agency that the Trump administration announced earlier this year.

The workforce cuts and reorganisation of the country's diplomatic corps are part of a wider administration effort to reduce the size of the federal government that has been largely carried out by the Department of Government Efficiency, formerly led by Elon Musk.

A recent ruling by the Supreme Court cleared the way for the layoffs to start, while lawsuits challenging the legality of the cuts continue to play out.

Michael Rigas, the department's deputy secretary for management and resources, said in a statement that select staffers would be informed if they were being laid off and called it part of the department's biggest reorganization in decades.

“Soon, the Department will be communicating to individuals affected by the reduction in force. First and foremost, we want to thank them for their dedication and service to the United States,” he said.

It wasn't immediately clear how many people would be dismissed.

In late May, the State Department notified Congress of an updated reorganisation plan, proposing cuts to programs beyond what had been revealed earlier by Rubio as well as an 18 per cent reduction of staff in the US, even higher than the 15 per cent initially floated in April.

Rigas' statement said the department is aiming to “focus resources on policy priorities and eliminate redundant functions, empowering our people while increasing accountability.”

Critics say the scale of cuts floated will lessen US influence globally and make it hard for many departments to carry out their missions.

The State Department is planning to eliminate some divisions tasked with oversight of America's two-decade involvement in Afghanistan, including an office focused on resettling Afghan nationals who worked alongside the US military. It also intends to eliminate programs related to refugees and immigration, as well as human rights and democracy promotion.

The American Foreign Service Association, the union that represents diplomats, urged the State Department last month to hold off on job cuts.

Notices for a reduction in force, which would not only lay off employees but eliminate positions altogether, “should be a last resort,” association President Tom Yazdgerdi said. “Disrupting the Foreign Service like this puts national interests at risk — and Americans everywhere will bear the consequences.”