The former top Russia expert at the White House has said she has been subjected to a campaign of harassment and intimidation, including death threats, which reached a new peak after she agreed to testify in congressional impeachment hearings.

Fiona Hill, who was the senior director for Europe and Russia in the National Security Council (NSC) said other NSC staff had been “hounded out” by threats against them, including antisemitic smears linking them to the liberal financier and philanthropist, George Soros, a hate figure on the far right.

In her testimony to Congress, a full transcript of which was released on Friday, Hill described a climate of fear among administration staff.

The UK-born academic and biographer of Vladimir Putin said that the former ambassador to Ukraine, Marie Yovanovitch, was the target of a hate campaign, with the aim of driving her from her post in Kyiv, where she was seen as an obstacle to some corrupt business interests.

Yovanovitch was recalled from Ukraine in May on Trump’s orders. In a 25 July conversation with the Ukrainian president, Volodymyr Zelenskiy, Trump described Yovanovitch as “bad news” and predicted she was “going to go through some things”. The former ambassador has testified she felt threatened by the remarks.

Trump’s lawyer, Rudy Giuliani, led calls for Yovanovitch’s dismissal, as did two of Giuliani business associates, Lev Parnas and Igor Fruman. All three are under scrutiny in hearings being held by House committees looking at Trump’s use of his office to put pressure on the Ukrainian government to investigate his political opponents.

“There was no basis for her removal,” Hill testified. “The accusations against her had no merit whatsoever. This was a mishmash of conspiracy theories that…I believe firmly to be baseless, an idea of an association between her and George Soros.”

“I had had accusations similar to this being made against me as well,” Hill testified. “My entire first year of my tenure at the National Security Council was filled with hateful calls, conspiracy theories, which has started again, frankly, as it’s been announced that I’ve been giving this deposition, accusing me of being a Soros mole in the White House, of colluding with all kinds of enemies of the president, and of various improprieties.”

She added that the former national security adviser, HR McMaster “and many other members of staff were targeted as well, and many people were hounded out of the National Security Council because they became frightened about their own security.”

“I received, I just have to tell you, death threats, calls at my home. My neighbours reported somebody coming and hammering on my door,” Hill said, adding that she had also been targeted by obscene phone calls. “Now, I’m not easily intimidated, but that made me mad.”

“When I saw this happening to Ambassador Yovanovitch, I was furious,” she said, pointing to “this whipping up of what is frankly an antisemitic conspiracy theory about George Soros to basically target nonpartisan career officials, and also some political appointees as well.”

In Yovanovitch’s case, Hill said: “the most obvious explanation [for the smear campaign] seemed to be business dealings of individuals who wanted to improve their investment positions inside of Ukraine itself, and also to deflect away from the findings of not just the Mueller report on Russian interference but what’s also been confirmed by your own Senate report, and what I know myself to be true as a former intelligence analyst and somebody who has been working on Russia for more than 30 years.”

Hill dismissed the suggestion that Ukraine meddled in the 2016 election was a “conspiracy theory” intended to distract attention from Russia’s well-documented role.

The treatment of Yovanovitch, Hill said “had a really devastating effect on the morale of all of the teams that I work with across the interagency because everybody knows Ambassador Yovanovitch to be the best of the best in terms of a nonpartisan career official.

The former national security official, who resigned in July, said she thought that the fact that Yovanovitch was a woman in a high position also played a role in the attacks.

“I don’t see always a lot of prominent women in these positions – she was the highest ranking woman diplomat,” Hill said.