WASHINGTON, Sept. 5 (Xinhua) -- The New York Times published an anonymous op-ed on Wednesday that it said was penned by a senior Trump administration official who has vowed to thwart parts of the president's agenda and "his worst inclinations."

In the piece titled "I Am Part of the Resistance Inside the Trump Administration," the author wrote that while many senior officials "want the administration to succeed," they are "working diligently from within to frustrate parts of his agenda."

"We believe our first duty is to this country, and the president continues to act in a manner that is detrimental to the health of our republic," the unidentified official wrote.

In a note attached to the op-ed, The Times said it's publishing the anonymous piece at the request of the author whose identity is known to it and "whose job would be jeopardized by its disclosure."

"We believe publishing this essay anonymously is the only way to deliver an important perspective to our readers," the note added.

The author denounced in the piece the president's "amorality" and described his impulses as "generally anti-trade and anti-democratic" and his leadership style as "impetuous, adversarial, petty and ineffective."

The op-ed also revealed that Trump's Cabinet originally speculated about invoking the 25th Amendment, which would start a complex process for removing the president, but they did not go with it because "no one wanted to precipitate a constitutional crisis."

In response, Trump questioned the existence of the author via Twitter on Wednesday.

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

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

Trump earlier told reporters the article was a cowardly product of dishonest media.

In a statement, White House press secretary Sarah Sanders said the person behind the op-ed chose to "deceive, rather than support, the duly elected President of the United States" and called on the "coward" to resign.

Sanders also urged The New York Times to issue an apology.

The release of the op-ed also came amid excerpts from an explosive book, titled "Fear: Trump in the White House," which painted a chaotic White House run under Trump.

Trump said the book, written by U.S. veteran investigative journalist Bob Woodward, "means nothing" and called it a "work of fiction."

Woodward said his book was based on hundreds of hours of conversations with direct players, which is to be released next week.

Woodward has been a reporter at the The Washington Post since 1971 and remains an associate editor there.

He is most famous for breaking the story of the Watergate scandal, which promoted the resignation of Richard Nixon from the presidency in 1974.