A senior Trump administration official has claimed to be part of a group “working diligently from within” to thwart the US President until he is out of office, in an unsigned opinion piece published in The New York Times.
Donald Trump said it was “gutless” and “the Times must, for National Security purposes, turn him/her over to the government”.
Mr Trump tweeted “TREASON?”, followed by: “Does the so-called “Senior Administration Official” really exist, or is it just the failing New York Times with another phony source?
“If the GUTLESS anonymous person does indeed exist, the Times must, for National Security purposes, turn him/her over to the government at once!”
The writer said: “Many Trump appointees have vowed to do what we can to preserve our democratic institutions while thwarting Mr Trump's more misguided impulses until he is out of office."
‘Cold comfort in this chaotic era’
The newspaper described the author of the column only as a senior official in the Trump administration.
The author added: “It may be cold comfort in this chaotic era, but Americans should know that there are adults in the room.
"We fully recognise what is happening. And we are trying to do what's right even when Donald Trump won't."
Appearing at an unrelated event at the White House, US President Trump lashed out at the Times for publishing the piece.
Mr Trump said: "They don't like Donald Trump and I don't like them."
Press Secretary Sarah Huckabee Sanders accused the author of “putting his ego ahead of the will of the American people”.
She said: “He is not putting country first, but putting himself and his ego ahead of the will of the American people.
"The coward should do the right thing and resign."
Ms Sanders also called on the Times to "issue an apology" for publishing the piece, calling it a "pathetic, reckless, and selfish op-ed".