Pennsylvania education and health officials on Thursday updated their safety guidelines for schools that hope to reopen in the fall, including directing them to ensure students remain at least six feet apart all day long — a provision that threatens to upend plans in some districts.

That guideline, instructing schools to implement social distancing “to the maximum extent feasible,” was on a list that also included having students eat in their classrooms and be screened by their parents for coronavirus symptoms each morning. The six-foot standard had previously been recommended, but some districts had moved ahead with plans for less. Thursday’s announcement from Harrisburg had administrators instantly questioning if they would have to consider a model more dependent on remote learning.

“The six-foot-distance [recommendation] is really going to make us go back and reevaluate our structure,” said Christopher Marchese, superintendent in the Avon Grove School District, adding that it had been “quite an afternoon.” Health officials in his county, Chester, had previously said a three-foot minimum would be acceptable in classrooms where six was not viable. The Bucks County Health Department had issued similar guidance.

The new guidelines came one day after Gov. Tom Wolf announced new restrictions on Pennsylvania’s bars, restaurants, and indoor gatherings meant to head off a coronavirus resurgence and give the state’s schools a chance to reopen. And it followed Philadelphia School District officials’ unveiling of their plans on Wednesday, which would have most of the 125,000 public school students going to school two days a week and learning remotely on other days — a model that stirred panic among many parents.

With the same issues everywhere, there’s little consensus on the best blueprint. New Jersey’s governor Thursday announced plans to spend millions to ensure students across his state have internet access for remote learning, while Pennsylvania’s largest teachers’ union urged Wolf to direct public schools to plan for all-online instruction.

“It is absolutely essential that every public school entity in Pennsylvania is prepared to deliver online instruction,” Pennsylvania State Education Association president Rich Askey wrote to Wolf and Education Secretary Pedro Rivera.

Askey said educators want to return to school, but “an increasing number of Pennsylvania educators and parents are concerned that reopening schools for in-person instruction poses significant health risks that, in the current environment, may be impossible to completely prevent.”

The debate over how — and whether — to reopen schools is causing anguish across the country, as Americans watch coronavirus cases and deaths reach worldwide highs. More than 3.5 million people had been infected and more than 138,000 had died in this country as of Thursday, according to Johns Hopkins University.

Pennsylvania’s guidelines aren’t mandatory, but state officials have the authority to close schools in a health emergency, as Wolf did when the pandemic broke out in March. State officials declined to speculate Thursday if a new surge would force them to do so again.

“It’s very hard for me to predict what things will be like in the fall,” Health Secretary Rachel Levine said. “What we absolutely need to do now is everything we possibly can” to enable a safe reopening, including wearing masks and abiding by state restrictions.

The new guidance provides a list of best practices that largely track with previous recommendations from the state, though they were presented as “minimum standards” endorsed by the Health Department for all pre-K-12 schools, whereas previous guidance listed “possible considerations” identified by education officials.

West Chester Area School District superintendent Jim Scanlon said in an email to families Thursday evening that the guidance means the district “will need to move toward a hybrid model that reduces capacity, with some students learning in school, distanced 6 feet apart, while others learn at home.”

“Our schools simply do not have the capacity or space to maintain this distancing with all students in our buildings at the same time,” Scanlon wrote.

Before the state’s announcement, the Bucks County commissioners said they hoped discretion would be up to individual counties. “If there is a difficulty in the Southwest part of Pennsylvania and we’re not having any problems, I would not want us to keep the kids home from school,” said Commissioner Diane Ellis-Marseglia.

She also announced that the county would buy every public and private school student a face shield so they can “all start off together with the same protection.”

Asked Wednesday whether he was prepared to pull the plug on reopening schools if needed, Wolf said, “Yeah. Yeah. I mean, ultimately, I don’t think it’s going to be me pulling the plug — it’s going to be ... teachers not wanting to come back to schools, parents not wanting to send kids to school.”

New Jersey, meanwhile, pledged $54 million in grant money to connect about 230,000 students to computers or internet access, Murphy said at a news conference outside an Irvington, Essex County, elementary school.

“We are committed to bridging the digital divide among our students in the long term,” Murphy said. “We will not leave districts to figure this out on their own.”

The governor said he expects virtual instruction to be part of the 2020-21 school year for most children in the state. School districts, including nonpublic schools, will be able to apply for the grants, which will be funded by federal coronavirus relief programs as well as New Jersey’s virus relief fund.

Under the state’s guidelines, public school students will receive in-person instruction at least part-time. Full reopening plans are being developed locally by each school system.

Nearly two million school-age children in New Jersey lack computer or internet access. Murphy said he would seek further philanthropic support to put technology in students’ hands.

Increasing delays in the return of test results from national laboratories are making it more difficult for officials to know how the virus is currently spreading nationwide, and Philadelphia Public Health Commissioner Thomas Farley said that’s causing challenges in accurately tracking the virus’ spread in the city on a day-to-day basis.

Philadelphia on Thursday reported 157 new confirmed coronavirus cases, an increase in line with recent daily totals for the city despite spikes in the region and in other states.

Gyms in Philadelphia can reopen Monday, Farley announced, with strict social distancing rules and masks required. Gyms are already open in the rest of the state; Wolf’s guidance Wednesday asked them to “prioritize” outdoor fitness activities.

The city will conduct unannounced inspections of gyms to ensure the facilities are following safety rules. Gyms that violate rules or that are found to be related to newly confirmed coronavirus cases will be shut down. And Farley warned they could be ordered to close again if case counts rise in the city.

Pennsylvania reported 781 new cases on Thursday. Echoing reports from state officials, Bucks County Health Director David Damsker said the county has seen an “uptick” in cases from out-of-state travel to places like South Carolina, the Jersey Shore, and Florida.

The commonwealth also earmarked more grant funding for employers grappling with the coronavirus: In a move he said was aimed to increase the pay of frontline workers, Wolf announced Thursday $50 million in grant funding to help employers in vital industries provide hazard pay during the pandemic.

The money will go to industries including health care, social assistance, hospitals, residential care facilities, transit, food manufacturing and retail, security, and janitorial services, according to the Governor’s Office. Eligible employers can contact Department of Community and Economic Development for information and apply at esa.dced.state.pa.us before July 31.

“Our frontline workers have put themselves at risk every day in order to continue to provide life-sustaining services to their fellow Pennsylvanians, and this funding will increase their pay in recognition of those sacrifices,” Wolf said in a statement. “These grants will help businesses retain employees, ensure that Pennsylvanians keep working, and avoid disruption of critical goods and services.”

Staff writers Sean Collins Walsh and Ellie Silverman contributed to this article.