Fortunately, a teacher managed to disarm her before she could inflict further damage, reports said.

The incident took place at the Rigby Middle School in Rigby, about 145 kilometers southwest of Yellowstone National Park.

According to Jefferson County Sheriff Steve Anderson, the girl pulled out a handgun from her bag and started firing indiscriminately.

Reports added that a female teacher managed to disarm and restrain her until cops arrived.

Law enforcement officials are presently investigating the case and looking for a motive.

Police haven't released the girl's name yet.