NASHUA, N.H. -- Authorities say all schools in Nashua will be closed Monday due to a detailed threat of violence directed toward two schools in the district, officials said.
A Nashua Police Department lieutenant said a school administrator received the threat via email on Sunday. That administrator contacted police.
School district Superintendent Mark Conrad said in a statement that students and staff at Nashua High School North and Nashua High School South were threatened with harm.
The police department, school administration and state and federal agencies are working to determine the credibility of the threat.
Conrad says the district is being "cautious" and schools will be closed out of safety.
There are 17 public schools in the district, with more than 11,000 students, notes CBS Boston. Parents were alerted to the closure through the district's phone alert system, the station says.
Administrators said it's a tough decision to shut schools for the day.
"For every parent who might say, 'Why did you close,' there will be other parents who say, 'You should have closed if there was a threat," Conrad told CBS Boston.
Conrad said schools are likely to reopen Tuesday.
Lieutenant Kerry Baxter says schools in the district will have extra patrols on Monday.
An investigation is ongoing.