"There is evidence the virus is already present in the communities we serve, and our efforts now must be aimed at preventing its spread," said a joint statement from LAUSD and the San Diego Unified School District, which serve a combined 750,000 students. "We believe closing the state's two largest school districts will make an important contribution to this effort."
At a morning news conference, Superintendent Austin Beutner reiterated that there was no confirmed case of COVID-19 in the LAUSD.
"We've been following the guidance of public health experts on how we can keep all who are part of our school community -- students, staff, families and visitors -- safe in the midst of a growing health crisis," Beutner said.He described the shutdown as an "appropriate path" now that the pandemic was at a point "where the balance has shifted."
The move came after a unanimous vote by the LAUSD board, including board member Nick Melvoin, who said it "wasn't an easy decision, it's one we didn't take lightly."
WATCH: Superintendent Austin Beutner announces LAUSD closure
As of Friday afternoon, there were 40 confirmed cases of novel coronavirus in Los Angeles County.
Asked about the possibility that the closure will last more than two weeks, Beutner said: "We don't have a crystal ball."
"The facts and the circumstances will tell us," he added.
Forty family resource centers will be opened throughout the district to continue to provide care for families that need it.
WATCH: Superintendent Beutner explains LAUSD closure
The LAUSD had already declared a state of emergency over novel coronavirus.
School districts throughout Southern California have already announced plans to temporarily close or shift to online instruction as part of nationwide efforts to contain the spread of COVID-19.
The LAUSD teachers union on Thursday urged the district to follow those examples.
"We are calling for the rapid, accelerated, and humane closure of LAUSD schools," UTLA President Alex Caputo-Pearl said. "Other countries have shown that a proactive - not reactive - approach slows the spread of the virus, makes sure healthcare providers are not crushed with overwhelming demand, and dramatically reduces fatalities."
MORE: The latest updates on novel coronavirus in SoCal
LAUSD made an emergency declaration earlier this week, but that didn't require the closing of schools. The district has not had any known coronavirus cases in students.
The emergency declaration authorizes Superintendent Austin Beutner "to take any and all actions necessary to ensure the continuation of public education," including relocating students and staff and provide alternative educational program options.'' It also provides employees with paid leaves of absence due to quarantine.
On Wednesday, the district canceled all large student and staff gatherings, including off-campus visits by students and staff to public places where crowds may gather. Student events and competitions may continue, but without spectators, the district said.
In addition, use of school facilities by outside organizations is canceled, and anyone who traveled outside the country in the past 14 days is not allowed on school campuses or in administrative offices.
WATCH: LA County Superintendent of Schools recommends all county schools close
Plans were already underway earlier this week in the event schools were forced to close.
"Kids belong in school and for working parents, they need to be with supervision. In my case, we sometimes don't have access to internet," said LAUSD parent Patricia Trujillo.
Trujillo lives in Venice with her two sons who are in the 8th grade. She says she wouldn't be able to stop working amid school closures and is worried her kids won't be as productive.
"At the end of the day, they're kids and if they might want to pay attention or might not be focused and would rather be playing basketball," she said.
Trujillo's sons may have to learn on tablets that the district is trying to purchase. They've asked the state for $50 million to cover the cost.
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Beutner has also reached out to companies like AT&T and Verizon to assist with connectivity. Many LAUSD families don't have home Wi-Fi or computers.
"We can pre-populate devices with some learning, but unless we have that two way communication, we would be limited in some of the instruction we can do," Beutner said.
Beutner says frequent hand washing and good hygiene practices are already taking place and the emergency declaration will allow for more resources to clean schools top to bottom.
Thousands of LAUSD students rely on the district for food, something that wouldn't be stopped if schools close.
"We serve over a million meals a day. I don't think it's likely we'll deliver to home, but we have more than a 1,000 campuses throughout the community," Beutner said. "I think there's ways we could keep those safe for distributing lifeline supplies."
For parents who still have to go to work, Beutner said that's not just a LAUSD problem, but a city, county and state problem that would need to be addressed together.
City News Service contributed to this report.