MEMPHIS, Tennessee (AP) — A gun went off inside a young student's backpack in a U.S. school cafeteria Thursday, but no one was hurt, officials said.

The student was a kindergartner, or about 5 years old. The child was being questioned by police and could be expelled.

A news release from the Shelby County school district said school staffers immediately took control of the backpack.

The statement said there was no evidence of harmful intent. The gun fired as students were waiting for the opening bell.

The child was detained and was being questioned by officers, with the child's mother present. Police spokeswoman Karen Rudolph said investigators were trying to determine how the gun ended up in the backpack.

"Weapons of any kind are prohibited on campuses, and this student will be disciplined in accordance with the state's zero tolerance policy," the school district's statement said.

The policy calls for "certain, swift and reasoned punishment" for students who bring drugs or guns to school.

It could include expulsion.