WASHINGTON, April 20 (Xinhua) -- Anthony Fauci, a top expert on infectious disease in the United States, urged caution on Monday for U.S. states to reopen, as anti-quarantine protests are popping up around the nation.

"Clearly this is something that is hurting from the standpoint of economics and the standpoint of things that have nothing to do with the virus, but unless we get the virus under control, the real recovery economically is not going to happen," Fauci, directer of the National Institute of Allergy and Infectious Diseases, said on ABC's "Good Morning America."

"So what you do if you jump the gun and go into a situation where you have a big spike, you're going to set yourself back," the key member of the White House coronavirus task forces continued. "So as painful as it is to go by the careful guidelines of gradually phasing into a reopening, it's going to backfire. That's the problem."

Protests against stay-at-home orders meant to curb the spread of COVID-19 are flaring up in some states, as attendees argued that restrictions were unnecessary or have gone on too long, despite warnings from health experts that relaxing them too soon could cause additional infections and even more economic harm.

New Jersey Governor Phil Murphy, a Democrat, said on Monday that reopening the state, which has reported more than 85,000 confirmed cases and over 4,300 deaths, must be "careful" and "strategic."

"This is a two-part scenario - securing the public health situation so you can have confidence as you get back as we reopen our economy. Right now, that confidence does not exist," Murphy tweeted. "Reopening our economy today would backfire on us two-fold - a large spike in #COVID19 cases, and no customers at our stores because people are still fearful for their health and that of their kids and families."

Mike DeWine, Ohio's Republican Governor, who has announced that the state will begin the process of reopening on May 1, said on Monday that they are "trying to let businesses open back up, while not putting us at risk of having the whole healthcare system overwhelmed and then have to shut them down again."

"We're trying to get it right, but we understand this is very difficult for everyone out there," DeWine acknowledged.

According to a tally from Johns Hopkins University on Monday, the number of coronavirus cases in the United States has reached over 766,000, with more than 40,000 deaths.