A suspect who was armed with a rifle is in custody and a school employee has been rushed to the hospital following reports of an active shooter at a Houston prep school, local authorities said.

Houston police said a call about reports of an active shooting came in at 11:45 a.m. at 4400 Anderson Road at Hiram Clarke, the address for YES Prep Southwest Secondary.

Houston Police Chief Troy Finner said in a press conference Friday that officers arrived to the scene “within minutes” following the call and once inside the school came upon the suspect “armed with a rifle” and he “surrendered without incident.”

The gunman was not named, but identified as a 25-year-old Black male who was a former student of the school.

“When he came to the building, the front door, the glass door, it was locked. He gained entry by shooting on the glass door and immediately fired upon one of the employees of the school,” Finner said.

The employee, described as a white male, sustained a gunshot wound to the back.

Officers administered first aid to the victim and he was taken to the hospital. Finner described him as in “serious condition” and he is in surgery.

YES Prep Southwest Secondary said in a statement that “no students have been injured.” The school serves grades 6 through 12.

Audio from a dispatch call reveals an official said: “I’m gonna need units at 4411 Anderson Rd, just got a message that there’s a man with a gun in the school.”

The Houston Fire Department told ABC News one person was transported to Memorial Hermann Texas Medical Center Emergency Room. Their age, gender and condition are unknown at this point.

First responders are actively clearing the building and there are no reports of other injuries at the moment, Houston Fire said.

A seventh grader who was evacuated from the school told ABC Houston station KTRK, “When I was coming out, I saw blood and glass shattering everywhere.”

“My teachers told me to stay back in the classroom where nobody can see you and officers came, saying, ‘Put your hands up. Go outside,’” the student said.

A staging area for parents was set up at West Fuqua and Hiram Clarke and students were sent to that location.

The students had gone through active shooter training just two days earlier. Finner commended students for remaining calm during the evacuation.

Finner said there are no other potential suspects and no further threat to the students.