A house party in Stone Harbor, N.J., that has caused 25 Avalon lifeguards to quarantine; two conferences at a church in Delaware where members have tested positive for the coronavirus; a 700-person party in Jackson Township, N.J., that took police five hours to break up.

Officials on Monday pleaded with people to stay outdoors, keep distanced, and wear masks if attending social gatherings. Citing a Long Beach Island party where at least 35 attendees were infected with the virus, New Jersey Gov. Phil Murphy said people can get together but should do it outside.

“You’re playing with fire if you gather indoors without face coverings, without social distancing. There’s no good that will come from this,” Murphy said Monday.

In recent days, New Jersey authorities have responded to several reports of large gatherings, including the 700-person party at an Airbnb in Jackson Township.

A coronavirus outbreak was also spreading among the Miami Marlins, who played the Phillies on Sunday. By Monday, at least 13 Marlins players and coaches had tested positive for the virus and were expected to quarantine in Philadelphia.

Infections continued rising rapidly in a number of states, including Kentucky, which closed all bars and imposed tight restrictions on indoor restaurant operations on Monday — the latest state to backtrack on reopening in response to increasing cases.

Several other states need to do the same, White House virus response coordinator Deborah Birx told reporters in Kentucky on Sunday, saying that Ohio, Indiana, Tennessee, and Virginia need to close bars and limit gatherings to 10 people.

“We have another set of states right behind that we’re conveying the same message” to, Birx said. “Because we can see what is happening in the South moving North.”

Pennsylvania reported 839 new cases Monday as the surge that began in the middle of June continued. The commonwealth is now averaging more than 930 new cases a day over the last seven days, according to data analyzed by The Inquirer.

Though New Jersey’s positivity rate was 1.72% on July 23, according to the governor, the rate of transmission in the state was beginning to creep up. The state reported 446 new cases Monday.

In Camden County, police arrested the owners of the Bellmawr gym that defied the state’s shutdown orders, and the entrance to the gym was boarded up. The Atilis Gym owners were charged with contempt and violation of a disaster control act after failing to heed a court order issued by a judge Friday, authorities said.

Philadelphia’s rate of positivity has remained steady around 5%, indicating that the number of people getting tested had increased in recent days, officials said. Since Friday, 500 new cases have been reported, the city said Monday.

After virus-related delays in trash collection, city recycling pickup was suspended Monday and Tuesday so crews could catch up on the trash, the Streets Department said.

Philadelphia released an interim racial-equity plan on Monday aimed at decreasing the risk of coronavirus infection in communities of color. The plan followed city data published this month that showed that Black patients accounted for 60% of COVID-19 hospitalizations in Philadelphia.

The findings in Philadelphia echo national data that suggest Black and Latino people are at greater risk of contracting the virus and experiencing severe complications. Long-standing societal and health-care inequities mean workers of color hold a disproportionate number of essential-worker jobs and Black people suffer from underlying health conditions at higher rates than white people.

Under the plan, the Philadelphia Department of Health intends to add more test sites, improve access to food and housing for individuals who need to quarantine after testing positive, and make essential workers more aware of their rights.

With coronavirus cases rising, if slowly, in all of Philadelphia’s collar counties, one school superintendent said the increasing numbers made “COVID-19-related instruction disruption a matter of when, not if.”

Cheltenham School District students will begin school entirely remotely in September if its school board signs off, the superintendent announced Monday, citing an “alarming increase in cases in Pennsylvania and across the country.”

Wagner Marseille, chief of the district of about 4,000 students, said in a note to the community that he could “live with the recommendation to open in a fully virtual model. I can’t live with returning our students and staff too soon and risking jeopardizing their lives.”

The district could reopen later in the year with a hybrid instruction model or fully face-to-face “depending on the mitigation” of the virus. The school board is set to consider the plan Aug. 3.

The announcement followed the decision of another sizable suburban district, Downingtown, which last week also announced a completely virtual opening in September.

With evidence from contact tracing indicating that the virus spreads more easily indoors, some authorities said outdoor activities appeared not to be causing outbreaks.

Murphy said on CNN on Monday morning that recent case spikes have been traced to indoor parties, suggesting distanced outdoor recreation on beaches is safe.

“The evidence we have is, beaches, parks, the peaceful protests outdoors — folks have handled themselves really well, and we don’t see a whole lot of spread from any of that activity,” Murphy said, speaking from his home in Middletown. “The evidence is overwhelming that the virus is a lot more lethal indoors.”

In Avalon, where members of the beach patrol were quarantining after a party that was attended by at least one person with the coronavirus, beach patrol officials said they haven’t “traced anything back to activities outside.”

And in Delaware, public health officials urged anyone who recently attended conferences or services at the Destiny Christian Church in Dover to be tested for the virus. Two conferences at the church drew a few hundred people over the past two weekends, officials said, and three members of the church had tested positive for the virus.

“Knowing your COVID-19 status is one of the most important things you can do to prevent spread of the virus,” said state Health Director Karyl Rattay.

This story has been updated with the correct location of the 700-person party.

Staff writers Allison Steele, Sarah Gantz, Laura McCrystal, Rob Tornoe, Ellie Rushing, and Anna Orso contributed to this article.