The US Department of Education said on Tuesday it would lay off nearly half its staff, a possible precursor to closing altogether, as government agencies scrambled to meet US President Donald Trump's deadline to submit plans for a second round of mass layoffs.

The terminations are part of the department's "final mission," it said in a press release, alluding to Trump's vow to eliminate the department, which oversees US$1.6 trillion in college loans, enforces civil rights laws in schools and provides federal funding for needy districts.

The layoffs would leave the department with 2,183 workers, down from 4,133 when Trump took office in January.

It's the latest step in Trump's sweeping effort to downsize the government, led by the world's richest person Elon Musk and his Department of Government Efficiency (DOGE).

DOGE has cut more than 100,000 jobs across the 2.3 million-member federal civilian bureaucracy, frozen most foreign aid and cancelled thousands of programmes and contracts, despite dozens of lawsuits challenging the legality of those moves.

All US government agencies have been ordered to come up with large-scale layoff plans by Thursday, setting up the next phase of Trump's cost-cutting campaign.

Several agencies have offered employees payments to retire early to fulfill Trump's demand.

The Education Department said affected employees will be placed on administrative leave starting on March 21.

The union representing more than 2,800 department workers said it would fight the "draconian cuts".

Meanwhile, NASA announced on Tuesday the dismissal of its chief scientist and others, marking the latest in a series of administrative actions undermining climate change research.

While the move affects only 23 people, a spokeswoman indicated more cuts are coming.

The first round notably eliminates the Office of the Chief Scientist, led by Katherine Calvin, a renowned climatologist who contributed to key UN climate reports. She and other US delegates were also barred from attending a major climate science meeting in China last month.

Also eliminated are the Office of Technology, Policy, and Strategy, and the Diversity, Equity, Inclusion, and Accessibility Branch of the Office of Diversity, Equity, and Inclusion.

NASA has so far avoided the deep cuts affecting other agencies, reportedly due to last-minute intervention by Jared Isaacman, Trump's nominee for NASA chief.

Isaacman, an e-payments billionaire and SpaceX customer, is seen as close to Elon Musk.

Trump, who has called climate change a "scam" and expressed disdain for the UN and climate science, has already pulled the US out of the Paris Agreement for a second time.

Meanwhile, his administration has dismissed hundreds of employees at the National Oceanic and Atmospheric Administration (NOAA), the nation's other key climate agency, with more cuts expected. (Agencies)