A 13-year-old student wearing a dark green trenchcoat and carrying an assault rifle fired one shot in a middle school Monday morning and told two administrators, "please don't make me do this," officials said.

No one was injured, and the student was taken into custody.

The student, who was not identified, pointed the gun at two other students as he entered Memorial Middle School and was confronted by an administrator, who tried to talk him into putting down the Mac-90 assault rifle, said Joplin police spokesman Lt. Geoff Jones.

The administrator, Assistant Superintendent Steve Doerr, told the student, "You don't have to do this, there is another way," Superintendent Jim Simpson said.

The boy refused to put the gun down and fired one shot into the ceiling. Doerr then went into a nearby office to call police.

The student kept trying to fire, but the rifle jammed. The student then left the building, followed by another administrator. Police arrived shortly after and arrested the boy as he crouched behind a nearby building.

Joplin police Officer Curt Farmer said officers found a note in the student's backpack saying that he had placed an explosive in the school, which has about 750 students. The backpack also contained military manuals, notes on how to build an improvised explosive device and detailed drawings of the school.

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

Students in the school were moved to a nearby building.

Later Monday, police searched the suspect's home and removed rifles and handguns. A patrol also used bomb-sniffing dogs and officers to search the school but nothing was found, Jones said.

Simpson said police told him the boy had a fascination with the deadly Columbine High School shooting in Littleton, Colorado, in 1999, but police declined to verify that information.

School administrators said Simpson told them the student had no major disciplinary problems and "no indication of why he was doing this."

Jones said the weapon belonged to the suspect's parents. Police said it was not uncommon for people in the area to own assault weapons.

The shooting happened about 7:45 a.m. (1145 GMT), 10 minutes before school started.

Deron Moore, an eighth-grader, said the school was locked down and an announcement was made that someone with a gun had come into the school.

"A lot of the kids were scared," Deron said. "After they said on the intercom that there was someone with a gun, I kind of went into shock."

Schools across the United States have been on alert after three deadly school shootings in three states in the span of a week, and several schools have been locked down or closed entirely during the past two weeks because of threats.

In Pennsylvania Amish country Monday morning, church bells tolled across the region in remembrance of the five young girls who were shot to death at their one-room schoolhouse one week earlier.