People wearing masks pass by a store closing soon in Santa Monica, California, on Tuesday, amid the coronavirus pandemic. Photo: AFP

US top infectious disease expert Anthony Fauci warned on Wednesday that several US states including Ohio, Tennessee, Kentucky and Indiana should be vigilant to avoid COVID-19 surges experienced in the southern and western parts of the country.

Fauci, director of the US National Institute for Allergy and Infectious Diseases, said that on a conference call with governors a day earlier, he "made that point to them that it is very important to get ahead of the curve."

Ohio, Tennessee, Kentucky and Indiana are among those states starting to show a subtle increase in "percent positives" -- the percentage of total tests with positive results, Fauci said in an interview with ABC.

That is "a surefire hint that you may be getting into the same sort of trouble with those states that the southern states got into trouble with," he said.

Fauci said on MSNBC that adherence to five principles could help stop coronavirus surges happening in states, including universal wearing of masks, avoiding crowds, physical distancing of at least six feet, typical hand hygiene and avoiding bars or closing them where possible.

"If we don't start initiating rather strict adherence to the five principles I just mentioned," Fauci said, "what inevitably is going to happen is that the states that are not yet in trouble will likely get into trouble."

Fauci's warning came as US COVID-19 death count surpassed 150,000 on Wednesday.

More than 4.4 million COVID-19 cases have been reported in the United States with the fatalities reaching 150,090 as of Wednesday evening, according to a tally by Johns Hopkins University.