(NEXSTAR/WAVY) – A messaging app used by teachers and parents in school systems across the country said Wednesday that an explicit image sent to parents late Tuesday was part of a “coordinated attack.”

Teachers from several states, including Virginia, said the image was circulating at their schools, according to Motherboard.

Natalie Allen, a spokeswoman with Virginia Beach City Public Schools (VBCPS), confirmed to 10 On Your Side, “Some of our elementary school parents received inappropriate content that resulted from the nationwide misuse of the app, but not students or teachers.”

Allen said the school system temporarily suspended the app’s messaging features at all Virginia Beach schools.

The school system sent elementary school parents and staff the following information:

VBCPS parents and staff,

We were recently made aware that the messaging feature of the Seesaw app was misused and inappropriate content was sent to accounts nationwide. Virginia Beach City Public Schools has disabled the message feature on this app until Seesaw resolves the issue. Thank you for your understanding in this matter.

Sincerely,

Virginia Beach City Public Schools

NBC News said a screengrab from a Florida parent showed the image, which it said was a meme “infamous on the internet” that showed a man “engaged in an explicit act.”

The San Francisco-based company said in a news release that the platform itself was not hacked and that they suspect someone used compromised email-password combinations to log into Seesaw accounts.

“We have no evidence to suggest this attacker performed additional actions or accessed data in Seesaw beyond logging in and sending a message from these compromised accounts.”

In a statement to Nexstar Wednesday, Seesaw said it continues to monitor the situation and has already notified impacted users. They did not, however, comment on how many users received the image.

On the company’s website, Seesaw says that it is used by “over 10 million teachers, students, and family members every month across more than 75% of schools in the U.S.”

Troy City School District in New York warned parents Wednesday of “unauthorized messages” that could contain inappropriate photos or links.

“Please do not read or click any links until Seesaw has resolved the issue,” the District said on Facebook. “We will send an update when we receive it.”

Seesaw blamed a “credential stuffing” attack, which involves bad actors using stolen login credentials to attempt to log in to an unrelated system.

Seesaw temporarily disabled the messaging feature and adjusted its detection and blocking rules to prevent future attacks. The app is urging all users to create unique passwords that aren’t used in other services.