Some school districts around the country have started to ban the use of Zoom for online learning from home during the coronavirus crisis because of growing concerns about security, and others are reassessing how and whether to use the teleconferencing platform.

Days after the FBI issued a warning to the public about the “hijacking” of online classrooms and teleconferences, the New York City Department of Education, which runs the largest school district in the country, said teachers should no longer use Zoom and should instead work through Microsoft Teams.

Other school districts, too, have banned Zoom or are trying to beef up security around its use. Clark County Public Schools in Nevada said in a statement that it had decided to “disable access to Zoom out of an abundance of caution due to instances of hacking that created unsafe environments for teachers and students,” but that it was looking at options to that might allow it to resume access.

Zoom said in a new statement on Saturday:

Zoom takes user privacy, security, and trust extremely seriously. Zoom was originally developed for enterprise use, and has been confidently selected for complete deployment by a large number of institutions globally, following security reviews of our user, network and datacenter layers. During the COVID-19 pandemic, we are working around-the-clock to ensure that hospitals, universities, schools, and other organizations across the world can stay connected and operational. As more and new kinds of users start using Zoom during this time, Zoom has been proactively engaging to make sure they understand Zoom’s relevant policies, as well as the best ways to use the platform and protect their meetings. We have encouraged our education users in particular to follow the guidance contained here: — and we recently updated the default settings for education users enrolled in our K-12 program to enable waiting rooms and ensure teachers are the only ones who can share content in class by default. We are proud of the role we are playing during this challenging time and committed to providing educators and other users with the tools they need.

The FBI issued a warning to the public earlier this week about the “hijacking” of online classrooms and teleconferences after it received reports of disturbances by people shouting racist and threatening language and displaying hate messages. It said saboteurs were hacking into online meetings in a phenomenon now called “Zoombombing,” because Zoom has become the most popular teleconferencing choice for K-12 schools and colleges and universities during the pandemic.

Concerns about online security have been rising as most of the nation has moved to online education, with school buildings closed to try to stem the spread of the novel coronavirus that has stopped public life around the world. Schools have rushed to put together online lessons and programs, sometimes without strict security filters. There have been numerous reports of intruders disrupting classes and school meetings, from elementary school to higher education.

For example, University of Florida President W. Kent Fuchs reported an intrusion of a student government meeting by someone who displayed racist messages, swastikas, pornography and death threats.

Teachers in New York City were just sent updated guidance from the city’s education department on video conferencing, which said that after reviewing requests by students, teachers and service providers to credential Zoom, security and privacy issues on the platform were raised. “Based on the DOE’s review of these documented concerns, the DOE will no longer permit the use of Zoom at this time,” the document says.

Danielle Filson, a spokeswoman for the city’s Education Department, said in a statement:

Providing a safe and secure remote learning experience for our students is essential, and upon further review of security concerns, schools should move away from using Zoom as soon as possible. There are many new components to remote learning, and we are making real-time decisions in the best interest of our staff and student. We will support staff and students in transitioning to different platforms such as Microsoft Teams that have the same capabilities with appropriate security measures in place.

In Los Angeles, some elementary-school teachers have already stopped using Zoom because of intruders, the Los Angeles Times reported.

The Alpine School District in Utah is reassessing the use of Zoom after a phone call with elementary school teachers was disrupted with a display of pornography, KATU reported. The principal, Kyle Hoopes, apologized on Facebook, saying that he would in the future send out links via parent message and not share it publicly and “will probably use a different platform” such as Google Meet.

In the Edmonds School District in Washington state, officials have taken steps to tighten security around the use of Zoom and other online platforms. Lynwood Today reported that teachers have been told to offer Zoom meeting information only in private forums, such as email, and participants to a Zoom meeting will not have to turn on video once they are in the meeting.

On social media, some people are posting videos of classes they have hacked, and putting out calls for students to provide information on when classes are being held and how to log in. The Washington Post reported this week that thousands of personal Zoom videos have been left openly viewable on the Web. Space X and NASA have both banned the use of Zoom because of security issues.

Amelia Vance, director of youth and education privacy at the nonprofit Future of Privacy Forum, told my Post colleague Laura Meckler that there is now a lot of confusion about how to navigate the online world.

“When you have companies like Zoom announce they were going to make their products free in full for educators, a lot of people were very thankful,” she said, and she heard from educators, districts and administrators who asked whether security was “genuinely an issue.”

“First and foremost I’ve been pushing really hard on making sure that educators and administrators are using tools that were made for education,” she said. “There is a very complex legal landscape around student privacy, and products made for consumers generally, for offices, for adults are unlikely to comply with those laws.”

She almost feels “a little bad for Zoom on this one because it’s not something unique for them,” she said, noting that Internet trolls are nothing new. She also said that Zoom had originally made it “easy for those abusing the platforms to do so” but now the company appears to be moving to address security issues.