Washington, Sep 6 (IANS): An unnamed senior US administration official has assailed President Donald Trump's "amorality" and reckless decision-making in an op-ed and said he or she is part of a "resistance" working to thwart Trump's worst impulses.

"The dilemma -- which (Trump) does not fully grasp -- is that 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 New York Times piece read. "I would know. I am one of them."

Trump labelled the anonymous writer "gutless" and the newspaper as "phony". His press secretary said the mystery writer was a "coward" who should quit, the BBC reported.

The NYT said disclosing the name of the official, who is known to the publication, would jeopardize the official's job, and that publishing the piece anonymously was the only way to deliver an important perspective to readers.

Major newspapers almost never publish unnamed op-ed pieces. At The New York Times, it is very rare, but not entirely unprecedented, the CNN said.

The op-ed came on the heels of reports based on a damning book about Trump's presidency by veteran journalist Bob Woodward and amplified the sense that top advisers to the President have serious concerns about his conduct in office and leadership abilities.

It is likely to compound Trump's sense of paranoia that he is surrounded by advisers who may be duplicitous and untrustworthy, the CNN report added.

Trump quickly lashed out on Wednesday, dismissing the op-ed as "really a disgrace". He demanded for the name to be revealed.

"We have somebody in what I call the failing New York Times that's talking about he's part of the resistance inside the Trump administration," Trump said. "This is what we have to deal with. And you know the dishonest media ... But it's really a disgrace."

He then pivoted to his accomplishments, claiming that "nobody has done what this administration has done in terms of getting things passed and getting things through."

Trump later tweeted a pointed and unsubstantiated attack on the NYT, questioning if the author of the op-ed exists. If the author does exist, the organization should publicly identify the individual, Trump said.

"Does the so-called 'Senior Administration Official' really exist, or is it just the Failing New York Times with another phony source?" Trump tweeted.

"If the GUTLESS anonymous person does indeed exist, the Times must, for National Security purposes, turn him/her over to government at once!"