Updated

The 13-year-old boy who fired a single shot from an assault rifle inside a middle school was charged as a juvenile Tuesday in the bloodless shooting.

The boy, who entered Joplin Memorial Middle School wearing a mask, was charged with first-degree assault, armed criminal action and making terrorist threats. Officials of the Jasper County juvenile office said they were talking with a prosecutor about possibly charging the boy as an adult.

The student fired one shot into the ceiling of a school entryway Monday after confronting administrators and students. Nobody was injured and he left after his gun jammed, police said.

Another hearing is set for Wednesday, the juvenile office said.

Nearly all students returned to classes at the school Tuesday, officials said. Police officers and patrol cars were stationed near the school but largely out of sight to avoid frightening sixth- through eighth-grade students, police Sgt. Curt Farmer said.

The boy's name was not released because of his age.

Assistant Superintendent Steve Doerr, who happened to be visiting the school, was among the first to encounter the 13-year-old student.

The boy pointed the weapon at two students and a teacher, then told Doerr: "Please don't make me do this."

Doerr responded: "You don't have to do this, there is another way."

The student then fired the shot into the ceiling.

"I would classify this as a very dangerous situation, a life-threatening situation," said school superintendent Jim Simpson.

"We were lucky."

The boy's Mac-90 rifle, a replica of an AK-47 assault rifle, jammed after the first shot, police said. The rifle belonged to his parents, who told police they kept it in a gun safe.

Doerr and Principal Steve Gilbreth persuaded the youth to leave the building. He walked out, followed by Gilbreth, who used his handheld radio to tell police the boy's location.

The student's backpack contained military manuals, instructions on assembling an improvised explosive device and detailed drawings of the school, which has 750 students.

"This was quite well thought-out," police officer Curt Farmer said. "He had been planning this for a long time."

Lt. Geoff Jones said the boy's motives were unclear. School officials said the student had no major disciplinary problems.

Simpson said police told him the boy had a fascination with the Columbine High School shooting in which 15 people were killed in 1999 near Littleton, Colo. Police declined to comment.

The student was wearing a trench coat — like the student gunmen at Columbine — and had a mask or hood fashioned out of a white T-shirt with two holes cut out for his eyes.

Joplin, which has about 40,900 residents, is in southwest Missouri. It is about 10 miles from the small town of Riverton, Kan., where five high school students were arrested in April and accused of plotting a school rampage.

Schools across the country have been on alert since recent school shootings. In Pennsylvania, church bells tolled Monday in remembrance of the five young Amish girls killed at their one-room schoolhouse one week earlier.