Several top United States officials have denied that they are the author of an anonymous editorial that attacks US President Donald Trump.
A New York Times article, said to be written by a senior White House official, says Mr Trump's appointees are trying to stifle his agenda.
There is fierce speculation over who is responsible - with the US vice-president among those to deny any involvement.
Mr Trump has described the writer as "gutless" and the newspaper as "phony".
A spokesperson for US Vice-President Mike Pence has dismissed claims that he wrote the op-ed, describing it as "false, illogical and gutless".
Several other Cabinet members and top officials have also denied writing the piece.
Secretary of State Mike Pompeo attacked the writer as a "disgruntled, deceptive bad actor".
"I come from a place where if you're not in a position to execute the commander's intent, you have a singular option - that is to leave," Mr Pompeo said.
Meanwhile, a spokesperson for Treasury Secretary Steven Mnuchin described the anonymous piece as "irresponsible", while a spokesperson for the Secretary of Homeland Security Kirstjen Nielsen said: "These types of political attacks are beneath the secretary and the department's mission".
The article - entitled I Am Part of the Resistance Inside the Trump Administration - is written by someone the New York Times describes as a senior official in the Trump administration.
The paper says the author requested anonymity and that this was essential to deliver an "important perspective" to its readers.
"Many of the senior officials in his own administration are working diligently from within to frustrate parts of his agenda and his worst inclinations," the article says.
"I would know. I am one of them."
Although the writer says they support the administration's objectives, its successes have come in spite of the president, who is described as impulsive, erratic and amoral, someone whose "misguided impulses" need to be controlled for the good of the US.
"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," it says.
In response, Mr Trump made several comments on Twitter, including "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 government at once!"
White House press secretary Sarah Huckabee Sanders said the author was "not putting country first, but putting himself and his ego ahead of the will of the American people. This coward should do the right thing and resign".
Meanwhile, First Lady Melania Trump said: "If a person is bold enough to accuse people of negative actions, they have a responsibility to publicly stand by their words."
The White House is already on the defensive amid questions over Mr Trump's suitability for office raised in a book by revered political journalist Bob Woodward.
The book, Fear: Trump in the White House, describes staff deliberately undermining the president, with some hiding sensitive documents from him to prevent him signing them, and other aides calling him an "idiot" and a "liar". Mr Trump has called the book a "con".
One of the most explosive passages in the New York Times article says there were "early whispers within the Cabinet of invoking the 25th Amendment", which would allow Mr Trump to be forced out of office.
That top officials are reportedly working against the elected US leader has raised some alarm and not just from the White House. In the Atlantic, David Frum, a Republican commentator who is a fierce critic of Mr Trump, called it a "constitutional crisis".
"What the author has just done is throw the government of the United States into even more dangerous turmoil," he wrote.
"He or she has enflamed the paranoia of the president and empowered the president's wilfulness."
A former CIA director, John Brennan, who has been strongly critical of Mr Trump, called the article "active insubordination" although he said it was "born out of loyalty to the country".
Others have wondered whether it was an attempt to distance the Republican administration from their president ahead of the important mid-term elections.
So far, officials who have said they did not write the editorial include:
Defence Secretary James Mattis
Secretary of State Mike Pompeo
Director of National Intelligence Dan Coats
Treasury Secretary Steven Mnuchin
Secretary for Homeland Security Kirstjen Nielsen
Secretary for Housing Ben Carson
Attorney General Jeff Sessions
Ambassador to the UN Nikki Haley
Office of Management and Budget Director Mike Mulvaney
Secretary for Veterans Affairs Robert Wilkie
Labour Secretary Alex Acosta
CIA Director Gina Haspel
Energy Secretary Rick Perry
Counsellor Kellyanne Conway
Environmental Protection Agency chief Andrew Wheeler
Agriculture Secretary Sonny Perdue
Small Business Administration chief Linda McMahon
Health Secretary Alex Azar
Transportation Secretary Elaine Chao
Commerce Secretary Wilbur Ross.