A U.S. judge on Thursday temporarily blocked the Trump administration's proposed buyout for federal workers until at least Monday, giving an initial win to labor unions that sued to stop it.

Even as the program was stayed, more than 60,000 federal employees have already accepted the buyout offer, a White House source said.

The ruling by U.S. District Judge George O'Toole in Boston pushes back a midnight deadline set by the Trump administration, which is pressuring federal workers to leave their jobs in an unprecedented drive to overhaul the federal government.