A teacher at a high school in Dalton, Ga., was arrested on Wednesday after he barricaded himself in his classroom and fired at least one gunshot through a window, the police said.

Bruce Frazier, the spokesman for the Dalton Police Department, said that no students were hit and that he was aware of only one injury: A student hurt her ankle while running through the halls.

The police identified the teacher as Jesse Randall Davidson, 53. They said that he appeared to have locked the door to his classroom at Dalton High School and was alone there when students tried to enter shortly before noon. The principal, Steve Bartoo, was called to the classroom and said he used a key to open the door.

“I attempted to enter the classroom and he slammed the door,” Mr. Bartoo said at a news conference on Wednesday afternoon, adding that Mr. Davidson told him to go away. “He had some nonsensical noises that were made as well.”