An argument that broke out Wednesday morning between two students in a classroom of a Northwest Washington high school ended when one shot the other outside the school as classes were being dismissed, police and school officials said.

Officers, with the help of school security staff, quickly arrested a teenager and confiscated a handgun, Assistant D.C. Police Chief Peter Newsham told reporters outside Coolidge Senior High school.

The wounded student was struck at least once in the leg about 3:15 p.m. and taken to a hospital, Newsham said. Authorities said the injuries were not considered life-threatening. No charges had been filed as of Wednesday evening.

Students who had not yet left the school, in the 6300 block of Fifth Street NW, were locked in their classrooms until police outside had secured the scene. There are about 550 students enrolled at Coolidge.

District Schools Chancellor Kaya Henderson called the shooting an “isolated incident,” and said “parents should feel safe bringing their students to school” Thursday. She said counselors and extra staff will be available for students.

Still, the swarm of police patrol officers, detectives and top commanders scouring a parking lot near the high school’s front entrance and the back end of the football field proved an unsettling sight .

“It’s unfortunate and not a very good feeling,” said Rochelle Murrell, who was picking up her 9-year-old daughter from the elementary school that is across the street from Coolidge and about 300 feet from where the shooting occurred.

“I don’t know what to think right now,” Murrell said, noting that her daughter, a fifth-grader, knew something bad had happened, even though it was connected to a different building. “I know she’s going to ask me and I’m going to have to tell her something. I’m always honest with her.”

During a news conference, police and school officials emphasized that the dispute involved only the two students and that nobody else had been in danger or targeted. “Obviously it’s troubling,” Newsham said. “But all the people inside the building were safe.”

Henderson said some students did witness the gunfire.

Authorities offered few details of how the shooting unfolded, but Henderson and D.C. Council member Muriel Bowser (D-Ward 4), who represents the area, confirmed that it was sparked by a classroom dispute late Wednesday morning.

Henderson said one student left the building and apparently returned as classes were being let out and targeted the classmate he had been arguing with. She declined to describe the nature of the disagreement.

KiJee Queen, 15, described herself as friends with both of the youths involved and said they had been arguing for some time over their style of dress. “They got into it in class today,” she said.

Newsham said only that the victim and suspect were in their late teens. He would not say precisely where the shooting occurred, but police were concentrating on a parking area toward the north end of the football field, near the high school’s front entrance.

Newsham said the shooting occurred on school property. Police had taped off an access road off Sheridan Street NW, near the elementary school. Officers on motorbikes and with dogs were scouring the grounds.

Bowser said she fielded 20 calls from worried parents. “My biggest concern was that neighborhood kids were involved,” she said. “And when neighborhood kids are involved, what happens in the school during the day can spill over to the community at night. That doesn’t appear to be the case here.”