St. Louis police say three people are dead, including the shooter, after a shooting at a high school Monday morning.

Speaking at a news conference, Police Commissioner Michael Sack said the three dead included a woman, a teenage girl and the shooter, described as a man about 20 years old.

The shooting just after 9 a.m. at Central Visual and Performing Arts High School forced students to barricade doors and huddle in classroom corners, jump from windows and run out of the building to seek safety.

Sack said security officials initially became alarmed when the shooter tried to get into the locked school building. He declined to say how the man got inside, armed with what he described as a long gun.

Officers “ran to that gunfire, located that shooter and engaged that shooter in an exchange of gunfire,” killing him, Sack said.

Sack declined to name the victims and did not say if the woman who was killed was a teacher.

Six other injured people were hospitalized. Sack said some suffered gunshot wounds, while others were struck by shrapnel. He did not provide any information on their conditions.

One student, 16-year-old Taniya Gholston, told the St. Louis Post-Dispatch she was in a room when the shooter entered.

“All I heard was two shots and he came in there with a gun,” Gholston said. “And I was trying to run and I couldn’t run. Me and him made eye contact but I made it out because his gun got jammed. But we saw blood on the floor.”

Another student, ninth-grader Nylah Jones, told the Post-Dispatch she was in math class when the shooter fired into the room from the hallway. The shooter was unable to get into the room and banged on the door as students piled into a corner, she said.

Sack said the shooting happened at 9:10 a.m. Crime tape was placed around the school and some parents arrived to pick up kids and check on their safety. The district, in a tweet, said students could be picked up at another school building or a nearby grocery store.

Central Visual and Performing Arts High School is a magnet school specializing in visual art, musical art and performing art with about 400 students. The district website says the school’s “educational program is designed to cre­ate a nurturing environment where students receive a quality academic and artistic education that prepares them to compete successfully at the post-secondary level or perform competently in the world of work.”

(AP)