The Montclair school district received notice Friday morning of an unspecified threat against several schools in Essex County.

District administrators contacted the Montclair Police Department and directed all students and staff to stay indoors, with a shelter-in-place at Montclair High School, according to an email schools Superintendent Jonathan Ponds sent to the school community on Friday.

Later that morning, the district heard from authorities that it was safe to resume normal activities, said David Cantor, executive director of communications and community engagement.

Lt. Terence Turner has not yet responded to questions about the threat.

"I want to thank the Montclair Police Department for its quick action and our principals and staff for maintaining a calm and orderly atmosphere at each school," Ponds said in the community message. "As always, the safety of our students is our highest priority."