St. Louis police say three people are dead after a shooting a high school Monday morning.

Speaking at a news conference, Police Commissioner Michael Sack said the three dead included an adult, a girl and the shooter.

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. Within minutes, the school was surrounded by dozens of police vehicles.

THIS IS A BREAKING NEWS UPDATE. AP’s earlier story follows below.

ST. LOUIS (AP) — Six people were injured Monday morning in a shooting inside a St. Louis high school.

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. Within minutes, the school was surrounded by dozens of police vehicles.

St. Louis Public Schools said on Twitter that the shooter was “quickly stopped” by police. A tweet from the police department said the shooter was in custody. No further details about the shooter were immediately released.

The FBI said in a statement later Monday morning that there was no longer an “immediate threat” at the school. Police told TV stations at the scene that the six injured included one person who suffered cardiac arrest, and the others suffered gunshot or shrapnel wounds. KTVI-TV, citing police, reported that the shooter was among the injured.

No further details about the injuries were immediately released.

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.

TV reports said officers entered the area with guns drawn shortly after 9 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.”