Anoka County sheriff's deputies arrested a youth who showed up at Andover High School on Monday afternoon and tried to harm students, the school's principal said, without offering specifics.

In an e-mail to parents, Principal Becky Brodeur wrote that school staff acted quickly to diffuse the situation, which she deemed "limited in scope," before sheriff's deputies arrived to arrest the youth, whose identity wasn't released.

"At about 4:30 p.m. today, school staff took decisive action to intervene as a student who is not enrolled at our school entered the building and attempted to harm Andover students," the e-mail said. "Law enforcement has determined there is no ongoing threat to student safety regarding this unusual incident and there were no weapons involved."

School officials were cautious about providing information about possible victims. Brodeur said that privacy laws prevented her from providing information about the "medical condition of students involved, but we are confident they will make a speedy and full recovery."

She said that student safety remained a top priority at the high school, enrollment 1,750, about half an hour north of Minneapolis.

No further details about the incident were immediately available on Monday night, and messages left for the Sheriff's Office weren't returned.