EXETER, N.H. (AP) _ A group of high school seniors were disciplined after they dressed in camouflaged clothing and masks and stormed the school cafeteria with squirt machine-guns and water balloons.

``It was quite scary, especially for our cafeteria workers who didn't know what was going on,'' school Superintendent Arthur Hanson said. ``To see these kids dressed as they were, in light of everything that is going on in the country, it had to be very frightening.''

The prank happened Monday, shortly after seniors were dismissed at the end of Class Day activities at Exeter High School. The group returned wearing face masks or stockings on their heads and began squirting students and lobbing the balloons.

No one was injured, so the school decided to handle discipline internally, he said.

The school identified 52 of the offending students and canceled their participation in a class trip to an amusement park. They also were ordered to perform three hours of community service at the school Wednesday. All but one showed up, and that was the result of a miscommunication, Hanson said.

Some of those involved in the prank were ``really terrific kids'' who apparently did not realize just how scary they would appear in light of recent school shootings around the country, he said.

``We reacted very swiftly,'' he said. ``We wanted everybody to understand this is very serious.''