Washington DC - A Republican-led Senate committee on Thursday voted to hold the country's former top infectious diseases official, Anthony Fauci, in contempt of Congress, in an escalation of efforts to blame him for potential Covid-19 pandemic missteps.

On the advice of his lawyers, Fauci last week invoked his constitutional right to stay silent to prevent self-incrimination under antagonistic questioning from Republican senators, as they probed him over unsubstantiated claims that the origins of the pandemic were covered up.

The party-line vote advances the extraordinary effort to prosecute the 85-year-old career government scientist, who spent decades as the nation's top expert in infectious diseases.

It stems from an initiative by Republican Senator Rand Paul, who had subpoenaed the now-retired Fauci to testify before the Senate Homeland Security Committee.

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Prior to the hearing, Paul released thousands of pages of the immunologist's personal diary.

Fauci indicated his lawyers believed Paul intended to entrap him in a slip-up that could result in perjury charges, so Fauci opted to invoke his Fifth Amendment right not to answer.

Paul, the committee's chairman, has indicated he intends to send the panel's recommendation straight to the Justice Department, which can decide whether to take the case.

Contempt resolutions generally would go through the full Senate, and bypassing that route would open fresh legal and political questions for President Donald Trump's administration.

Democrats on the panel voiced their disdain over the vote, with Senator Gary Peters accusing Paul of a "rushed investigation."

He said the vote could "harm our ability to conduct future investigations and disregards constitutional protections long recognized by the US Senate, all without making a reliable case that there is a legal basis for holding Dr Fauci in contempt."