President Joe Biden blasted a series of blistering "inappropriate personal attacks" by Republicans targeting his pick to serve as a top banking regulator, as he accepted her withdrawal Tuesday from consideration for the job.

Soviet-born Cornell University law professor Saule Omarova had been nominated as comptroller of the currency, a role overseeing two thirds of the US banking system -- or some 1,200 institutions with a combined $14 trillion in assets.

She pulled herself from consideration after her nomination was derailed by several Republican senators falsely implying she was a communist, as well as legitimate cross-party concerns about her past pronouncements on banking reform.

"As a strong advocate for consumers and a staunch defender of the safety and soundness of our financial system, Saule would have brought invaluable insight and perspective to our important work on behalf of the American people," Biden said in a statement.

"But unfortunately, from the very beginning of her nomination, Saule was subjected to inappropriate personal attacks that were far beyond the pale," Biden added.

At Omarova's confirmation hearing last month, hardline Republican Senator John Kennedy suggested that her childhood in Soviet-run Kazakhstan indicated a possible communist loyalty.

"I don't know whether to call you 'professor' or 'comrade,'" Kennedy told her in a remark that sparked accusations that Republicans were reprising the 1950s "red scare" witch hunts against alleged communists led by Senator Joseph McCarthy.

Comptroller of the Currency nominee Saule Omarova came under fire at her hearing before the Senate banking committee in November 2021 Comptroller of the Currency nominee Saule Omarova came under fire at her hearing before the Senate banking committee in November 2021 Photo: AFP / Jim WATSON

Omarova pushed back, telling Kennedy her family had suffered under Stalin's brutal regime and that she "could not choose where I was born."

But her nomination had always looked like a heavy lift, with all Republicans and some Democrats in the evenly-divided Senate voicing concern over her past banking policy proposals.

In a 2020 paper, Omarova proposed the Federal Reserve provide consumer banking services as a "cheaper and more efficient alternative" to private accounts. She also called for boards of the biggest banks to be allocated government representatives.

Republican Pat Toomey said there was cross-party agreement that her "self-proclaimed radical ideas for America's financial system were not suitable for our nation's top banking regulator."

But Senate banking committee chairman Sherrod Brown accused "powerful interests" of a "relentless smear campaign reminiscent of red scare McCarthyism."

Fellow Democrat Elizabeth Warren rebuked Republicans for a "vicious smear campaign... doing the bidding of giant banks that want to keep gobbling up smaller competitors."

"I deeply value President Biden's trust in my abilities... At this point in the process, however, it is no longer tenable for me to continue as a Presidential nominee," Omarova said in a statement.

Michael Hsu, the acting head of the agency since May, is now favorite to get the job instead.