The judge could opt to delay the buyout further or block it on a more permanent basis when he next considers the legal challenge by the unions at a hearing on Monday.

If the Trump administration reaches its goal of cutting 5% to 10% of staff, more than 100,000 people will leave the federal workforce, making it by far the largest layoff in U.S. history. The current record-holder is IBM, which cut 60,000 jobs in 1993.