GOP calls for an investigation and the resignation of Dr. Anthony Fauci have escalated following this week’s revelation that the National Institutes of Health (NIH) funded gain-of-function research on the coronavirus. 

The controversial research involves artificially engineering an animal virus in a laboratory setting to further examine how it becomes more easily transmissible and deadly to humans – a measure that Fauci told lawmakers was not utilized by the NIH.

INTERNATIONAL COMMUNITY 'COMPLICIT' IN GAIN-OF-FUNCTION RESEARCH: BOOK

But a letter from the NIH to Ranking Member Rep. James Comer of the House Committee on Oversight and Reform Wednesday admitted to a "limited experiment" conducted in order to test if "spike proteins from naturally occurring bat coronaviruses circulating in China were capable of binding to the human ACE2 receptor in a mouse model" – contradicting Fauci’s previous claims.

The firestorm that followed renewed demands by Republicans in Congress for the resignation of the infectious disease specialist.

"For the past year and a half, critical decisions for the whole country have hinged off of Dr. Fauci’s advice and decrees. Two presidents have used his advice as the basis for our nation’s response to COVID-19," California Republican Rep. Doug LaMalfa said in a statement to Fox News Friday.

"Yet here we have incontrovertible proof that he has been intentionally lying to Congress," he added. "Dr. Fauci must resign and should face prosecution for perjury."

NIH ACKNOWLEDGES US FUNDED GAIN-OF-FUNCTION AT WUHAN LAB, DESPITE FAUCI’S DENIALS

LaMalfa’s comments echo sentiments by at least 14 other House Republicans who called on Fauci to resign this summer following reports that the NIH funded controversial animal testing in foreign countries.

Tennessee Republican Sen. Bill Hagerty took to Twitter to voice his opposition and said, "He should resign immediately."

Iowa Sen. Joni Ernst has not called for Fauci’s resignation but said an investigation needs to be conducted.

CLICK HERE TO GET THE FOX NEWS APP

"The facts are clear: Federal funds were misspent on dangerous studies on coronaviruses and taxpayers were misled," she told Fox News Friday. "Instead of getting to the bottom of this, Dr. Fauci has repeatedly dismissed or denied what we now know to be true. There must be consequences, and the American people deserve a full investigation."

Fauci’s office did not immediately respond to Fox News’ request for comment.