A teacher in Dalton, Georgia was in custody on Wednesday after he barricaded himself in a classroom and fired at least one shot, police said at an afternoon press conference.

Dalton Police Department spokesman Bruce Frazier told reporters that students were trying to enter the classroom at Dalton High School around 11:30 a.m., but the 53-year-old social studies teacher wouldn’t let them inside.

Police identified the teacher as Jesse Randall Davidson.

He allegedly “forced the door closed,” and the students alerted an administrator who tried to enter using a master key.

Davidson then fired at least one shot with a handgun—but “apparently didn’t want the students involved in any way,” Frazier told reporters.

“That’s when the lockdown happened,” he said.

Panicked students posted videos on social media showing teens running and crying during the evacuation. One female student suffered an ankle injury in the resulting chaos, but no other students were wounded, police said.

Davidson’s condition was not immediately available on Wednesday.

“Obviously a crime has been committed, so we will be charging him,” said Frazier.

“When you hear this kind of call go out, if you've got a badge, you run to it,” he added. “Our people responded in a coordinated and professional way very quickly.”

The school posted a message on Facebook informing parents that it had shuttled students to a nearby convention center after the evacuation.

“I want metal detectors in the schools. Every one of them,” one parent commented under the alert. “For staff, students, and visitors.”

The incident comes just days after President Trump called for arming teachers two weeks after a gunman opened fire at a high school in Florida, killing 17 people.

Dalton is located about 91 miles northwest of downtown Atlanta, according to the Atlanta Journal-Constitution.