US government workers faced widespread confusion on Monday following conflicting advice over compliance with an Elon Musk-backed order to list their last week's work in an email or face termination.

Just 48 hours after an email asking "what did you do last week?" was sent, the office behind it clarified responses were voluntary, leaving agencies to decide their approach.

But as this new guidance was shared with federal agencies, President Donald Trump weighed in that workers who did not comply with Mr Musk's demand would be fired or "sort of semi-fired".

And later on Monday evening, Mr Musk reinforced the ultimatum, granting workers a final chance to respond.

The mail from the Office of Personnel Management (OPM) on Saturday, instructed recipients to reply with five examples of what they did over the past seven days, without revealing any classified information. The recipients were asked to respond by end of Monday.

Mr Musk, who is leading the Department of Government Efficiency (Doge), said that failure to respond would be taken as a resignation.

The comments fuelled backlash, with federal worker unions and activist groups filing a lawsuit in California to halt the email mandate.

Key agencies, including the Departments of Defense, Health and Human Services (HHS), Justice, and the FBI ? now led by Trump appointees ? instructed employees to ignore the directive. This led to widespread uncertainty, with some workers receiving contradictory messages over the weekend.

The result was widespread bafflement, as federal workers faced uncertainty over their employment. Many also expressed confusion at the competing guidance they had been given by their respective agencies.

"They're succeeding in driving us insane," one employee who works under HHS told the BBC, and asked not to be named for fear of retaliation.

On Monday afternoon, OPM held a call with the heads of human resources at federal agencies and said it was up to each entity to determine how they want to handle the directive employees received Saturday, according to CBS News, the BBC's US partner.

The same afternoon, President Trump told reporters at the White House that Mr Musk's demand was a "genius" move.

"There was a lot of genius in sending it," he said. "We're trying to find out if people are working and so we're sending a letter to people, please tell us what you did last week. If people don't respond, it's very possible that there is no such person or they're not working."

"And then if you don't answer like you're sort of semi-fired or you're fired because a lot of people are not answering because they don't even exist," Trump said.

Mr. Musk maintained he was acting on instructions from President Donald Trump.

"Subject to the discretion of the President, they will be given another chance," he wrote on X, apparently referring to workers who did not respond to his demand by the end of Monday. "Failure to respond a second time will result in termination."

"The email request was utterly trivial, as the standard for passing the test was to type some words and press send!" he said in another post. "Yet so many failed even that inane test, urged on in some cases by their managers. Have you ever witnessed such INCOMPETENCE and CONTEMPT for how YOUR TAXES are being spent?"

President Trump has tapped Elon Musk to find government waste and inefficiencies. The tech billionaire has earned criticism and praise for focusing much of his attention on US government workers.

Despite pushback from agencies led by Trump appointees, the White House insisted, "Everyone is working together as one unified team at the direction of President Trump". "Any notion to the contrary is completely false," White House press secretary Karoline Leavitt said.

The statement did not explain why different government agencies were giving different recommendations. (BBC)

Update news