A middle school student who allegedly confronted a girl with a knife and was later found with a backpack full of restraining devices and weapons faces a series of charges, including terrorism, Maricopa County Attorney Andrew Thomas said.

Thomas said Monday that the 14-year-old eighth grader at Powell Junior High in Mesa told police he planned to hold his class hostage.

The teen was charged with aggravated assault with a deadly weapon and kidnapping, both Class 2 felonies. He also was charged with carrying a weapon on school grounds, a Class 1 misdemeanor, according to information from Thomas office.

County officials say that two weeks ago, the teen had plotted a "Columbine-like" scenario, comparing his plans to the 1999 deadly shooting massacre at Colorado's Columbine High School.

The boy was arrested by Mesa police on March 23 at his home. Police said they discovered weapons in his backpack, including a loaded .25-caliber handgun with a full clip of bullets and one in the chamber, plus a box of bullets with about 28 rounds, Mesa Police spokeswoman Diana Tapia said.

Police also found three large knives, a lock, a metal chain and two rolls of duct tape in the backpack, Tapia said.

Police were alerted by a girl who said the boy confronted her with a knife.

Holly Hosac, another Mesa police spokeswoman, said the teen was a good student and apparently had trouble with another boy at school.

Bringing a weapon to school could result in a long-term suspension or expulsion, said Kathy Bareiss, spokeswoman for Mesa Public Schools.

The seriousness of the crimes prompted Thomas' office to decide to try the teen as an adult, according to Barnett Lotstein, spokesman for Thomas.

The case has not been assigned to a Maricopa County Superior Court judge yet, Thomas said.

If convicted of any of the offenses, the teen could face several years in prison, according to Lotstein.