Breaking: Fairfax County Public Schools, one of the nation’s largest school systems, will close Friday, officials announced late Thursday night.

Superintendent Scott Brabrand said administrators had been flooded with “genuine concerns” from parents who wanted the school system to shutter.

The school district — which serves 188,000 students in Northern Virginia — had previously vowed to stay open, announcing it would give students the day off Monday to allow teachers time to prepare for the possibility of online learning.

But on Thursday, Brabrand wrote: “Schools are closing in Maryland, and several other states, and a state of emergency was declared in Virginia. As a result, and in an abundance of caution, I believe it is prudent for FCPS to cancel school tomorrow to help ease parent, staff, and student anxiety.”

Extracurricular activities, interscholastic contests, after-schools programs and field trips are canceled through April 12, according to the school system’s website.

Students will still have Monday off from school, Brabrand wrote, and administrators will use that time to make a “long term” decision on whether Fairfax will close its doors.

 “This remains a very fast narrative,” he wrote, “and the situation Monday is likely to be very different than today.”

Hundreds of schools in Maryland and suburban Virginia are closing in coming days in response to the coronavirus pandemic as officials try to protect students and contain the spread of covid-19.

In Northern Virginia’s Loudoun County, all classes and other school activities are canceled through March 20, in a sudden measure taken by one of Virginia’s largest school systems.

In Maryland, State Superintendent of Schools Karen Salmon announced that campuses would be closed from March 16 to 27 — a two-week period that will cancel classes for more than 900,000 students in public schools across the state.

“It is crucial that we take immediate measures to slow the spread of covid-19 in school communities around the state,” Salmon said, appearing beside Gov. Larry Hogan (R) on Thursday as he announced a set of public restrictions.

Salmon said buildings and buses would be cleaned during the shutdown, and she recommended that the time off be made up during spring break. The state is working to continue providing school meals for students in need, she said.

The Archdiocese of Washington said Thursday night that its 93 schools — in the District and Maryland — would follow the Maryland public schools’ closing schedule.

With cases of novel coronavirus on the rise and school systems closing elsewhere throughout the country, many parents had a sense that classes could be canceled, but the reality left them with challenges in child care and work obligations.

Some wondered about the instruction and school meals students would miss, while others considered the implications for extracurricular activities and for sports and spring-break plans.

“The entire parent community is probably reeling right now, trying to figure out how they’re going to cope with a two-week close,” said Cynthia Simonson, president of the Montgomery County Council of PTAs.

Parent Tammy Clark said that while closing schools was the responsible decision, she is concerned about families in her community, many of which lack Internet access and have few child-care options.

Clark also wonders how the state will handle standardized tests that students take in the spring. Her older son, a junior in high school, is to take the SAT with his classmates at the end of March. And her younger son, an eighth-grader, is preparing for a high-stakes math test in spring.

“It’s unprecedented, so I’m curious to see how things fall,” Clark said.

In a recent letter sent to families, school officials said Montgomery will provide instructional materials online and in a “hard copy format.” A major concern has been equity in the 165,000-student system, which is Maryland’s largest. More than 55,000 students get free and reduced-price meals.

“We don’t want to leave some families out because they don’t have Internet access or devices,” schools spokesman Derek Turner said.

Similar concerns were expressed by Monica Goldson, chief executive of Prince George’s County Public Schools. Goldson said her county — with 82,000 students who receive free and reduced-price meals — would provide instructional packets for students but would not offer remote instruction.

“I cannot guarantee every child has technology and access to the Internet,” she said.

In Loudoun County, students, parents and staffers learned early Thursday about the decision by Loudoun County Public Schools to suspend classes for 84,000 students — a move that left many reeling. Later in the morning, Schools Superintendent Eric Williams appeared at a news conference to explain his action.

Classes in Loudoun will cease for the next week, and the system has no immediate plans for online learning. Officials said the school system is “developing guidance” for principals and teachers about virtual education if schools remain closed for a prolonged period.

Williams apologized for the inconvenience and strain the closures will put on students and families but said, “We know it’s the right decision.”

“We know our schools are at the nexus of this community, and we know that local, regional, national experts are encouraging school divisions to consider and implement mitigation strategies,” Williams said.

No cases of covid-19, the illness caused by the novel coronavirus, have been associated with the school system, Williams wrote in an email sent to families and staff Thursday.

The shutdown, he said, will give the district time to get more information about the potential threat and better assess how to proceed without jeopardizing students, teachers and staffers. All Loudoun schools will be thoroughly cleaned before the expected reopening on March 23.

As news of the closure spread, Loudoun County families and employees struggled to adjust to their new reality. Students spilled onto sofas to watch movies at home, rather than taking exams, and parents pondered how much they should shape their children’s unexpectedly free schedules.

Others were making more desperate calculations. Among them are substitute teachers who will not be able to earn pay during the shutdown, and families dependent on free and reduced-priced meals provided by the school system. Nicole Morris, the executive director of Women Giving Back, a Loudoun nonprofit that provides essentials to lower-income families, said her organization was flooded with requests for help after the announcement.

“A lot of our families did not get to prepare,” she said.

After promising at the news conference to develop a plan for feeding families, Williams emailed Loudoun families late Thursday to announce that officials would serve free breakfast and lunch at every school campus from 8 a.m. to 1 p.m. Roughly 15,000 families in the school district qualify, according to spokesman Rob Doolittle.

Because of the abruptness of the closures, many students still had personal items such as laptops, computer chargers and medicine in their lockers. Williams said schools would be open from 9 a.m. to 1 p.m. Friday for students and families to make short visits to retrieve belongings.

At least one school, Park View High in Sterling, will use that time to distribute food to families that need it. The school — where 70 percent of students come from low-income families — is rounding up every item in its food pantry, according to Principal Kirk Dolson, and will bag it and hand it out to students and parents Friday.

Morris — whose nonprofit serves many families attending Park View — is stepping in to help, too. Over the past 24 hours, she has converted her nonprofit, which normally collects clothing items, into a food distribution center.

Morris said the organization has gathered roughly 20 boxes of food so far, enough for maybe 200 families — a small fraction, she said, of those who need it.

“I know the school made this decision with our safety in mind,” Morris said, “but I do feel this is going to take a toll on a lot of the families in need. They’re going to be so much more vulnerable to the ripple effect of what this virus is causing.”

Jay Cuasay, who has an eighth-grader in Loudoun schools, feels fortunate he does not need to worry about food for the foreseeable future. He and his wife, Eileen Sarett-Cuasay, began stockpiling groceries several days ago, for fear of the virus.

The Cuasays are not especially concerned about the quality of their daughter’s education, either. Their house has reliable Internet access, so if the system shifts to online learning, that should not pose a challenge — which the couple said they know is not the case for everyone.

If the shutdown extends for a significant period, or should Loudoun County’s online offerings prove inadequate, the Cuasays — both of whom have graduate degrees — said they feel comfortable taking turns teaching their child.

“She certainly likes her teachers better than asking mom and dad, so I could see that not being the most ideal,” Jay Cuasay said.

But what’s most difficult is explaining the pandemic to their 13-year-old daughter. The teen, “a huge social butterfly,” wanted to go to a movie Thursday evening with friends, Eileen Sarett-Cuasay said, and she is unsure whether — or how — to tell her “No.”

The family was already canceling plans with friends and take extra handwashing precautions. But it has been hard to convince their daughter of the seriousness of the coronavirus and the threat it could pose to society, Jay Cuasay said, partly because no one can see a pandemic.

Eileen Sarett-Cuasay said she does not know what to tell her daughter, partly because she has never experienced anything like the coronavirus pandemic. She worries about the lasting effects on the teen.

“I just want to keep things as normal for her as possible,” she said. “It’s important for her to have a normal life.”

Perry Stein contributed to this report.