Washington (CNN) High-ranking Trump administration political appointees within the State Department improperly retaliated against a career civil servant, according to a long-anticipated report by the department's watchdog released Thursday.

According to the report, the appointees acted against the career official --an Iran expert in the Office of Policy Planning during Secretary of State Rex Tillerson's tenure -- due to false perceptions about her political views and her ethnicity.

The incident was one of five cases the State Department Office of Inspector General (OIG) examined in its more than a year-long probe into "allegations of improper personnel practices involving the Office of the Secretary." The investigation did not find evidence of improper practices in two of those cases, and findings were inconclusive in the other two. The report recommended disciplinary action for those who improperly retaliated.

The release of the report comes as the State Department has become embroiled in the House impeachment inquiry and career diplomats involved in that probe have found themselves targets of political attacks by the President Donald Trump and his allies. Morale within the career ranks of the department has plummeted. On Wednesday, Secretary of State Mike Pompeo downplayed reports of low morale as "more Washington insidery stuff."

It is also the second report from the inspector general's office on retaliation at the Department. The first , released in mid-August, found that top officials in the State Department's Bureau of International Organization Affairs subjected employees to "disrespectful and hostile treatment," accusations of disloyalty, and retaliation. The report also said the bureau's leadership "did not take significant action" to address these concerns.

Questions of loyalty

According to Thursday's report, political appointees including Brian Hook, then Director of the Office of Policy Planning and now the top State Department official on Iran, played a role in prematurely ending the work detail of "employee one."

"OIG concluded that improper considerations played a role in the early termination of Employee One's detail," the report said.

CNN has previously reported that this employee is Sahar Nowrouzzadeh. Despite the fact that she had begun her government service under the presidency of George W. Bush and served in bipartisan administrations, Nowrouzzadeh was perceived as disloyal to Trump, the report found. She was targeted as a "trusted Obama aide" who had "burrowed" into the department in a March 2017 article from the "Conservative Review" that was circulated among top officials in that office.

Hook's deputy at the time, Edward Lacey, "generally described career employees detailed to (the Office of Policy Planning) as 'Obama/Clinton loyalists,' stated that they were 'not supportive' of 'Trump's agenda,' and moreover represented that he had 'ousted' some detailees," the report said.

Another political appointee, Julia Haller, referenced Nowrouzzadeh's ethnicity in an email to fellow official and incorrectly said she had been born in Iran.

"As background, she worked on the Iran Deal, specifically works on Iran within (the Office of Policy Planning), was born in Iran and upon my understanding cried when the President won," Haller wrote.

"Ms. Haller told OIG that she added the comment about Employee One's perceived national origin because Ms. Haller believed it could raise questions of 'conflict of interest' because Employee One was assigned to work on Iran policy at the Department. Ms. Haller also believed the information was relevant because it could be an issue that could make Employee One ineligible for a security clearance if she had foreign contacts," the report said.

Another top Trump political appointee, Christine Ciccone, questioned whether Nowrouzzadeh had refused to shake a political appointee's hand on their first day. The OIG found no evidence that Nowrouzzadeh had done so.

Hook denied that any of these details played a role in ending Nowrouzzadeh's detail at the Office of Policy Planning, instead claiming he had been in talks with another candidate that he wanted to hire for the Iran portfolio. He also said he did not view her as a "go-getter," according to the report.

'Strikes at the heart of the career service'

However, the report offered a cutting critique of the now-special envoy for Iran.

"OIG cannot conclude that these representations, on their own, offer a convincing explanation as to why Mr. Hook agreed to end Employee One's detail when he did," the report said, adding that some the dates and details that Hook provided were not corroborated by other testimonies.

"OIG also concludes that Mr. Hook's acquiescence to the request to end Employee One's detail before its scheduled expiration without any reference to merit-based factors was also inappropriate," it noted.

"According to the (Foreign Affairs Manual), 'appointment, assignment, and promotion for all categories of personnel must be on the basis of merit.' The FAM notes that such policies exist 'to promote the most effective execution of each agency's responsibilities.' Failure to adhere to those policies hinders the effectiveness of the Department, and questioning the 'loyalty' and political opinions of career employees and circulating communications suggesting that a 'cleaning is in order' undercuts 'an atmosphere of open dialogue and trust.'"

"It also strikes at the heart of the career service, which envisions professional employees who serve across administrations," the report concluded.

'Loyalty to the US constitution, above all else'

In a statement provided to CNN, Nowrouzzadeh said, "It is my hope that the Inspector General's findings pertaining to my case help prompt action that will guard against any further such misconduct by members of this or any future administration."

"For nearly 15 years, I've been proud to serve our country, across Republican and Democratic administrations. I continue to strongly encourage Americans of all backgrounds, including those of Iranian heritage, to consider public service to our nation and to not be discouraged by these findings," she said.

"I also think I speak for many within what President Harry S. Truman during a critical time in U.S. history called 'the most loyal body of civil servants in the whole world' in saying that we should not fear, but rather value rigorous debate among colleagues with deep experience when formulating U.S. policy on matters critical to our national security. It is one of the ways we faithfully discharge our duties, as per our oaths and loyalty to the U.S. constitution, above all else," Nowrouzzadeh added.

In two letters to the inspector general, State Department counselor T. Ulrich Brechbuhl disputed some of the findings of the report.

"The Department disagrees with the finding in the report that improper considerations played a role in the early termination of Employee One's detail," Brechbuhl wrote in the October 30 letter, which was included in the report.

In another letter sent November 13 and included with the report, Brechbuhl wrote that the Department "appreciates the effort" by the OIG, but again reiterated that the "leadership disagrees with the Inspector General's conclusion."

Brechbuhl also noted that, "As current Department leadership was not in place during the time of the alleged behavior that was the subject of this investigation, it has no firsthand knowledge of the events."

"The Secretary will consider whether disciplinary action is appropriate for any Department employee who failed to comply with (Foreign Affairs Manual) provisions regarding the use of non-merit factors in personnel decisions," he said.