The Trump administration's ongoing mass firing of government employees has been put on hold, with a federal judge calling the move "likely illegal" and ordering the government to hand over evidence to prove it didn't violate the law.

An emergency ruling by a federal judge in California amounted to the broadest effort yet to halt the Trump administration’s overhaul of the federal government.

The courts are poised to tackle broad separation-of-powers arguments against the Trump administration’s historic cuts to the federal workforce, after a federal judge said the president likely violated the US Constitution.