Students and staff were evacuated from Fredericton High School Wednesday morning due to a bomb threat.

School administrators say they received a threat shortly after 9 a.m. that there may be an explosive device inside the building.

They quickly made the decision to clear the school of the more than 2,000 students and staff.

“The alarm went off and as soon as we left the school we seen the SWAT team and six cop cars show up and 20-plus cops got out,” says student Josh Woodworth.

Students tell CTV News they were ushered out of the building quickly and were not allowed to grab their jackets, leaving some standing out in below-freezing temperatures wearing only light clothing.

“No, they didn’t give us any time to get anything,” says Woodworth. “I was lucky. I had my sweater, but they told us we had to leave. Teachers didn’t give us any time to get anything out of our lockers.”

Some students and staff walked to a nearby French school to keep warm.

Police and fire crews responded to the school and quickly sealed off the area. Police used their bomb disposal unit to sweep the area and a tactical response team searched the school.

“It was a very thorough, detailed search,” says Fredericton Police Insp. Brian Ford. “We do have the floor plans so the search was conducted, all the floors and the rooms were checked off.”

Classes were cancelled and students and staff were dismissed for the day.

Shortly after the evacuation, a picture of a note began making the rounds on social media. It said four devices had been placed inside the school and indicated further threats at other schools if Wednesday’s failed.

“Had we found an explosive device, I probably would have put a little more credibility into that, but in the absence of any explosive device, I would rate that very low,” says Ford.

The incident remains under investigation. The school will reopen Thursday.

With files from CTV Atlantic's Andy Campbell