Parts of West Side School in Syosset are severely damaged after a three-alarm fire ripped through the building early this morning.

Nassau County Fire officials said an automated alarm went off in the school around 4:40 a.m.

According to investigators, no one was inside and the building was locked when the alarm first went off.

A total of 150 firefighters from 16 different departments in both Nassau and Suffolk counties helped with the response.

Heavy smoke blanketed the school campus and the surrounding neighborhood for hours. Crews finally got the main body of the fire under control before 7 a.m.

Cold Spring Harbor Superintendent of Schools Joseph Monastero said the fire did not affect any classrooms and was contained to part of the school that included the library, a community room, a creative learning lab and a boiler room.

The roughly 220 students in grades 2nd through 6th grade, who attend West Side, are completely off today as the district figures out where they'll learn the rest of this week.

“As of right now, the school is closed for today," Monastero said. "As we find out more from the fire department, we’ll make a plan where the students will be able to go to school going forward.”

Nassau County Fire officials said it's unclear if the school will be able to reopen in any way later this week.

Cold Spring Harbor Central School District Superintendent Joseph Monastero said in a statement:

"We want to begin by acknowledging how difficult the past day has been for our students, staff, and families. Events like this affect a school community deeply, and we understand that many of you are processing a range of emotions. Please know that the safety and well-being of our students and staff remain our highest priority. Our team has worked throughout the day to develop a plan that will support students and staff, maintain continuity of instruction, and restore a sense of routine while repairs are made to the West Side School building.

"We also want to thank the firefighters and all EMS for their quick response in putting out the fire. We will be open for in-person learning tomorrow with West Side students being sent to the other three school buildings. We thank our entire community for their continued patience and support."

The Cold Spring Harbor Board of Education has a pre-scheduled meeting tonight at 8 p.m.

No one was injured in the fire.

Nassau County Fire Marshal, fire investigators and NCPD Arson Bomb Squad detectives are investigating the cause of the fire.