WASHINGTON — President Donald Trump, forced to contend with the possibility that a senior member of his administration, along with others, may be trying to undermine his authority, erupted in private on Wednesday, according to multiple aides and allies familiar with his thinking. They described his mood as “volcanic.”

An anonymous opinion article published in The New York Times earlier in the day, which the newspaper said was written by a senior administration official, asserted that a handful of appointees, serving at the highest levels of the Trump administration, consider the president to be “amoral,” and on the precipice of dangerous decisions that could put the country at risk.

The president publicly described the article as "gutless" as his press secretary berated the author as a "coward" who, she suggested, should resign.

The article followed published excerpts from a forthcoming book by Bob Woodward that included examples of Trump’s own cabinet officials and senior aides balking at his orders, defying his commands and privately disparaging him to others.

The one-two punch comes as the FBI’s investigation, led by special counsel Robert Mueller, heats up.

Over the summer, the president’s former campaign chairman was convicted, his former lawyer pleaded guilty, the chief financial officer of his private company was granted immunity and a dozen Russian intelligence officers were indicted — all stemming from an investigation into whether Trump’s presidential campaign conspired with Russia. Trump is also the subject of a separate criminal investigation into whether he obstructed justice.

The president has refused to be interviewed by the special counsel, though people familiar with his legal strategy are hopeful he may be able to answer a limited number of written questions related to the Russia probe.

On Wednesday, those close to the president said he was enraged by both the book and the anonymous opinion piece, and one senior administration official expressed anger at the "betrayal" by an unnamed colleague.

Some close to the president speculated the story could add fuel to the president's ongoing battle with the media.

Trump is “not just furious with the person (who wrote it) but furious The Times would run an unsigned op-ed,” said one person close to the White House.

After staffers huddled behind closed doors in the minutes after the op-ed article was posted, strategizing a response, the president himself suggested on Twitter Wednesday that the author had committed treason. He then seemed to suggest that it was a fake.

TREASON? — Donald J. Trump (@realDonaldTrump) September 5, 2018

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! — Donald J. Trump (@realDonaldTrump) September 5, 2018

Echoing a sentiment shared by a person familiar with the president’s thinking, a former Trump aide suggested the op-ed article was an attempted “coup.”

“This is a coup. It’s an administrative coup, a soft coup, a kooky coup, whatever you want to think,” Michael Caputo told CNN.

White House officials, mounting a response reflecting intense anger at the article, said they did not know who wrote it. But finger-pointing was already underway, with questions about just how "senior" this official ultimately is. The New York Times did not respond to questions about how it characterized the op-ed's author.

On Thursday, two top administration officials — Vice President Mike Pence and Secretary of State Mike Pompeo — denied that they were behind the op-ed.

A source familiar with the thinking inside the White House described the mood late Wednesday as one of closing ranks. "We're in this together and we're focused on the policy and the political travel that the president has coming up," the person said. "It's serious work that we're doing." ‎

White House officials have spent much of the summer hunkered down amid an increasingly intensive FBI investigation and a string of foreign policy challenges from North Korea to trade negotiations to a collapsing Iran strategy.

The August death of Sen. John McCain, eulogized as an American hero though he was personally loathed by Trump, also cast a shadow on the presidency in recent weeks, stirring up resentments fueled by the president’s initial refusal to bestow some of the markers of honor and national grief on a lifelong public servant and former prisoner of war.

One person close to the president said a reference to McCain in Wednesday’s anonymous opinion article was a particular point of irritation for the president.

A former administration official still close to the White House expressed concerns that the mounting scandals and divisions plaguing the president would hamper any legislative agenda remaining in the first term.