U.S. authorities are granting enhanced personal security for Dr. Anthony Fauci, the nation's leading infectious disease expert, who is facing growing threats since the start of the coronavirus outbreak.

"Yesterday, upon the recommendation of the U.S. Marshals Service, the department approved the special deputization request from H.H.S. for nine H.H.S.-O.I.G. special agents to provide protective services for Dr. Fauci," the U.S. Justice Department said in a statement, referring to the Office of the Inspector General at the health department.

Dr. Fauci is the director of the National Institute of Allergy and Infectious Diseases and has been the most outspoken advocate of "social distancing" rules in the administration of President Donald Trump, which have in turn led to the closure of schools and businesses and the orders that keep people home.

Read more:

Trump extends federal social distancing guidelines to April 30

People defying stay-at-home orders, social distancing prompt D.C. man to deliver message from car

Online conspiracy theorists have accused the 79-year-old top expert of trying to undermine Trump as shutdowns have battered the country's economy, although a recent study conducted by the Imperial College in London validates the legitimacy of "social distancing." The guidelines could save millions of lives, the study said.

The Washington Post reported that safety concerns also include "unwelcome communications from fervent admirers," citing sources.

Dubbed as "an integral part of the U.S. government's response against COVID-19" by the U.S. Health Department, Dr. Fauci is one of the few people who would correct the Trump's misstatements.

In an interview with the journal Science on March 22, Dr. Fauci said: "I can't jump in front of the microphone and push him down."

"Let's try and get it corrected for the next time," he added.

As of Thursday, confirmed COVID-19 cases in the United States have surpassed 200,000, with over 5,000 deaths.