A suspect is in custody after a shooting at Marjory Stoneman Douglas High School in Parkland, Florida, left at least one person dead and multiple people injured Wednesday afternoon.

Broward Schools Superintendent Robert Runcie said there were “numerous fatalities” but the exact number was unknown. At least 14 victims have been taken to local hospitals, the Broward Sheriff said, and the scene is still active.

An afternoon fire drill at the school created a scene of chaos before gunshots were heard Wednesday afternoon.

School board officials said staff and students heard what sounded like gunfire shortly before dismissal, and the school went on an immediate lockdown.

Footage showed dozens of officers and ambulances at the school as students ran or walked out with hands up. Some reported victims were seen being carried out of the school.

Footage posted on social media showed students cowering under desks in one classroom as gunshots rang out.

Sen. Bill Nelson, D-Fla., told MSNBC just before 4 p.m. that “there were a number of fatalities,” citing Broward County officials, and that the shooter was not in custody, although authorities believed they knew who he was.

“This is a really bad day,” Nelson said.

NBC 6 spoke to the older brother of one student, who said his sister, a sophomore, was safe but “trembling in shock” at the scene unfolding at her high school.

“It’s just complete chaos out there,” he said a short distance from the school. “She was numb.”

NBC 6 also spoke with a father who was able to communicate with his child inside the school. “I’m relieved that [the suspect] has been captured, at least that part of its over. The stress from this is too much.” He said his child is safe.

Coral Springs Police tweeted that students and teachers should remain barricaded inside the school until officers can reach them.

“Worried parents of Douglas HS students, while this is Parkland scene (handled by BSO) we are assisting. We understand you are worried for your children (and nearby Middle School children, which was put on lock down as a precaution),” Coral Springs Police tweeted.

ATF agents were responding to the school to assist BSO and Coral Springs PD, officials said.

Florida Gov. Rick Scott said he has spoken with law enforcement about the shooting. President Donald Trump tweeted his “prayers and condolences to the families of the victims.”