President-elect Trump's national security spokeswoman is stepping back amid allegations of plagiarism. Here are four others who faced similar accusations. (Sarah Parnass/The Washington Post)

Monica Crowley, recently appointed by President-elect Donald Trump to a key national security communications job, said Monday that she would relinquish the post amid multiple allegations of plagiarism.

Crowley, who has been named senior director of strategic communications at the National Security Council, said in a statement that “after much reflection,” she had decided to remain in New York and “will not be taking a position in the incoming administration.”

“I greatly appreciate being asked to be part of President-elect Trump’s team and I will continue to enthusiastically support him and his agenda for American renewal,” Crowley said in the statement, in which she made no mention of the plagiarism charges.

The publisher of a 2012 book by Crowley said last week that it will stop selling copies until she addresses allegations of plagiarism. Crowley, a conservative pundit, is also under fire for allegedly plagiarizing passages in her PhD dissertation at Columbia University.

The plagiarism charges were originally reported by CNN and Politico.

Crowley was to have worked for national security adviser Michael T. Flynn, a retired Army lieutenant general.

“The NSC will miss the opportunity to have Monica Crowley as part of our team,” Flynn said in a statement. “We wish her all the best in her future.”

When the plagiarism charges first surfaced, the Trump transition team defended Crowley, putting out a statement praising her “exceptional insight and thoughtful work on how to turn this country around.”

“Any attempt to discredit Monica is nothing more than a politically motivated attack that seeks to distract from the real issues facing this country,” the statement said.

As a White House aide, Crowley would not have faced confirmation proceedings.

In the aftermath of her appointment, CNN reported that Crowley's book, “What the (Bleep) Just Happened?” lifted work from columnists, news reports, articles and think tanks without proper attribution.

“The book, which has reached the end of its natural sales cycle, will no longer be offered for purchase until such time as the author has the opportunity to source and revise the material,” publisher HarperCollins said in a statement last week.

Politico reported that Crowley’s 2000 dissertation contained more than a dozen sections of text that were lifted, with little to no changes, from scholarly works without proper attribution.

The dissertation was titled “Clearer Than Truth: Determining and Preserving Grand Strategy: The Evolution of American Policy Toward the People’s Republic of China Under Truman and Nixon.”