New Jersey became the latest state Monday to halt or reverse the reopening of indoor dining at restaurants and bars because of surging coronavirus cases, with Gov. Phil Murphy announcing on Twitter that scenes of overcrowding from across the state “CANNOT CONTINUE.”

“We had planned to loosen restrictions this week,” he said. “However, after #COVID19 spikes in other states driven by, in part, the return of indoor dining, we have decided to postpone indoor dining indefinitely,” he said.

The blunt message followed a flurry of similar announcements in Florida, Texas and California, where officials have ordered bars shuttered amid record-setting case numbers in recent days. In New York, Gov. Andrew Cuomo said Monday that he would decide in two days if indoor dining could resume in the country’s most populous city.

The Centers for Disease Control and Prevention and the National Restaurant Association have offered guidelines to newly opened restaurants and bars, but in interviews Monday, epidemiologists cautioned that they don’t think drinking establishments should serve patrons anytime soon.

“I’m delighted they’re closing some of them,” said John Swartzberg, a professor emeritus of infectious disease and vaccinology at the University of California, Berkeley. “I’m disappointed they’re not closing more. The reason I’m delighted is because the highest risk for people is being in an enclosed area for a prolonged period of time. Bars are a perfect set up for that.”

It can be difficult to remain socially distant, he said. It’s also hard to drink wearing a mask, and the more you drink, the worse your judgment becomes.

“They’re setting themselves up to harm themselves or harm others if they get infected,” he said.

In states where case numbers are rising, Swartzberg said that reopening shouldn’t just be frozen but reversed. “The whole process is going to be jerky — two steps forward, one step back,” he said. The process should stay that way until things get safer again — or until medication or a vaccine dramatically changes the virus’ trajectory, he said.

The recent surge in cases has affected younger adults at higher rates, according to Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. In testimony to Congress last week, Fauci attributed this to a “pent-up urge” to go out after months of being homebound.

Just how significant bars have been in driving up case numbers in states like Florida isn’t clear though, said George Rutherford, a professor of epidemiology at the University of California, San Francisco. But public health officials were clearly interpreting them as a contributor, he said. In California, he added, that data aren’t clear.

John Bodnovich, executive director of American Beverage Licensees, a national trade group for bars, said there was no consensus among owners over whether the closures were warranted.

“Some have closed voluntarily out of concern for their employees and their customers, whereas others have decided to stay open while taking increased measures to protect staff and guests,” he said. “Much is dependent on local circumstances.”

Bodnovich urged bar owners to follow local rules, though. In Texas and Florida, he said, authorities had enforced shutdown measures.

At a pub that reopened in Los Angeles earlier this month, no enforcement was necessary before it was shuttered last week. The pub, Casey’s, said in a Facebook post on Friday that it had tried to reopen safely and responsibly. But after an employee tested positive for the virus, a specialized crew was hired for a “medical-grade deep clean.” The entire staff will be tested for COVID-19, the disease caused by the coronavirus, and Casey’s will remain closed until further notice, the statement said.

The risk of eating at a restaurant isn’t too different from drinking at a bar if they’re both indoors, said Art Reingold, a professor of epidemiology at the University of California, Berkeley. He pointed to a recent study from China that traced a cluster of positive cases to a restaurant in Guangzhou, a city more than 600 miles south of Wuhan, where the coronavirus outbreak began.

The researchers, from the Guangzhou Center for Disease Control and Prevention, found that 10 people from three families who sat at different tables at the same time on Jan. 24 had likely become infected by a person seated with one of the families. The person showed no symptoms at the time, but the family had recently been in Wuhan. The researchers concluded that the virus was likely transmitted by air conditioning.

“To prevent the spread of the virus in restaurants, we recommend increasing the distance between tables and improving ventilation,” they said.

The National Restaurant Association, which represents half a million businesses in the United States, said in a statement that it is encouraging restaurants to follow its reopening guidance, a 10-page booklet available on its website, along with federal, state and local guidelines that urge social distancing and other measures.

Irwin Redlener, director of the Columbia University National Center for Disaster Preparedness, said that if restaurants do reopen, kitchen staff, servers and other employees need to be tested daily. “We need strict rules on outdoor dining, too,” he said. “Servers should wear masks and gloves.”

But Redlener said that he didn’t think it would be “feasible” for bars or restaurants to reopen until next year.

In New Jersey, Marilou Halvorsen, president of the state’s Restaurant and Hospitality Association, said that restaurant owners had spent thousands of dollars ordering food, rehiring employees and working on safety practices in anticipation of being able to reopen Thursday. The freeze imposed by the governor, she said, “will cause even more restaurants to fail.”

“We shouldn’t sentence an entire industry because of unprepared states and the bad acts of some bar operators,” she said.