New York (CNN) Diplomats are rallying to the support of former US ambassador to Ukraine Marie Yovanovitch after the release of a whistleblower complaint shed further light on the circumstances of her unexpected removal.

The allegations raised in the complaint, in combination with President Donald Trump's comments about the career diplomat revealed in the White House transcript of a call between Trump and his Ukrainian counterpart, lend further credence to the claim that Yovanovitch's removal from her post last May was politically motivated.

Two major groups representing the diplomatic community issued statements on Thursday with the American Academy of Diplomacy stating that Trump's comments are "deeply troubling."

Yovanovitch, a career member of the foreign service and who has served in ambassadorships under three presidents, was sworn in as ambassador to Ukraine in August 2016.

In May 2019, Yovanovitch was recalled to Washington, months earlier than expected. The State Department said at the time that Yovanovitch was "concluding her 3-year diplomatic assignment as planned" and that her departure aligned with the presidential transition in Ukraine.

However, the whistleblower cast doubt on that claim, writing in a complaint that "several US officials told me that, in fact, her tour was curtailed because of pressure stemming from" allegations by the then-Ukrainian Prosecutor General Yuriy Lutsenko -- the prosecutor with whom Rudy Giuliani had met to discuss "collusion."

"Mr. Giuliani subsequently stated in an interview with a Ukrainian journalist published on 14 May that Ambassador Yovanovitch was 'removed ... because she was part of the efforts against the President,'" the whistleblower wrote.

'The Achilles heel' of Ukraine

Yovanovitch was strongly committed to US foreign policy objectives in that country and outspoken in highlighting corruption in there, according to numerous former officials.

"She understood that corruption was the 'Achilles heel,' so to speak, of Ukraine," a former State Department official who knows Yovanovitch told CNN Thursday prior to the release of the complaint. "And so Masha, by doubling down on corruption and making it kind of her leitmotif of her tenure as ambassador, was doing exactly what she should have been doing and what US policy has been in Ukraine for quite some time."

That mission likely earned her Luksenko's ire. In late March, he claimed to The Hill's John Solomon that Yovanovitch had given "a list of people whom we should not prosecute." The State Department denied Lutsenko's claim, and Lutsenko later walked it back.

Nonetheless, Yovanovitch remained under fire by conservative outlets and figures. Donald Trump Jr. tweeted on March 24, "We need more ⁦@RichardGrenell's and less of these jokers as ambassadors," along with a link to an article from the conservative "Daily Wire" on growing calls for her to be ousted Giuliani has claimed without evidence on numerous occasions that Yovanovitch had impeded his investigation in Ukraine and has tied this baseless claim to a conspiracy theory involving funding from the billionaire George Soros.

The former State Department official said that "the fact that agents of the President, whether they be his son or Giuliani, should somehow be dragged into this mess on behalf of people who are unworthy and dubious at best is really distressing."

"We saw the knives were out for Masha but it was still shocking that she was forced to depart her post just weeks before she was going to go anyway," retired US Ambassador James Melville told CNN Wednesday. "That's just such a sign of disrespect, and almost contempt for career officers and diplomacy."

CNN has reached out to Yovanovitch for comment.

Secretary of State Mike Pompeo on Thursday said he had not yet read the whistleblower complaint.

'Deeply troubling'

Trump disparaged Yovanovitch in a call with his Ukrainian counterpart, a White House transcript released on Wednesday revealed.

"The former ambassador from the United States, the woman, was bad news and the people she was dealing with in the Ukraine were bad news so I just want to let you know that," Donald Trump told Volodymyr Zelensky in a July 25 call, according to a White House transcript released Wednesday.

Zelensky, who was elected in April 2019, echoed the US President's sentiment, saying "I agree with you 100%."

"She's going to go through some things," Trump added.

The American Academy of Diplomacy on Thursday said they noted Trump's comments -- particularly his remark that "she's going to go through some things" -- "with great concern."

"The threatening tone of this statement is deeply troubling," said AAD Chairman Thomas Pickering and AAD President Ronald Neumann, both of whom are retired ambassadors.

"It suggests actions outside of and contrary to the procedures and standards of a professional service whose officers, like their military counterparts, take an oath to uphold the Constitution," they said in a statement. "Whatever views the Administration has of Ambassador Yovanovitch's performance, we call on the Administration to make clear that retaliation for political reasons will not be tolerated.

In a statement Thursday, the American Foreign Service Association called "on all Americans to honor and respect the non-partisan, non-political work of the dedicated public servants of the U.S. Foreign Service."

"Our country needs a professional, non-partisan Foreign Service," the statement said. "Our members pledge their lives to service to their country and its interests. Any attack on their integrity and commitment to non-partisan service does a great disservice to them, to their families and to our country."

'One of the best'

Those who worked with Yovanovitch praised her experience and skill, and multiple former officials told CNN they thought she was an ideal choice for ambassador to Ukraine.

"Masha (Yovanovitch) knows that part of the world so well, speaks the languages, knows the issues cold," Melville said. "They couldn't have had a better ambassador than Masha."

Retired US ambassador Nicholas Burns on Wednesday described Yovanovich as "extremely effective," "highly ethical" and "a person of high character."

He also decried the President's comments about the longtime foreign service officer.

"It is so unprofessional of the President to do that -- to throw a US government employee under the bus, someone as distinguished as Ambassador Yovanovitch is," he told CNN. Burns, who served in the US government for nearly three decades, said he had not seen anything like it.

"It's injurious to morale and you can imagine how career people feel when they see one of the best people that we have, Masha Yovanovitch, treated like this," he said.

He called for "the higher levels of the State Department" to "come out and defend her."

"They should say she was a good ambassador, she did what was asked. She did what her constitutional duty asked her to do, represent the United States ably and honorably," Burns said. "She deserves an apology, a public apology."