Seventeen people died Wednesday after a shooter opened fire at a high school in Parkland, Fla., police said.

In an evening press conference, Scott Israel, the Broward County sheriff, said 17 people were confirmed to have been killed, including 12 within the building, two just outside, one who died on the street near the school, and two who died in the hospital.

Israel identified the shooting suspect as Nikolas Cruz, 19, who had been previously expelled from Marjory Stoneman Douglas High School, where the shooting took place.

"This incident truly makes me sick to my stomach," Israel said. "It's horrible. It's catastrophic."

Seventeen victims were brought to Broward Health, a system of medical facilities in South Florida, doctors with the hospital system told reporters during a press conference Thursday evening. Three remain in critical condition and three are stable. Several patients are still in surgery, they said.

Cruz was also brought to the hospital, but was later released into police custody.

Students and adults are among the victims, though Israel could not confirm whether any were teachers.

"We continually ask you in the media to continually put out the message if you see something, say something," he said. "If anybody has any indicator that someone is going through a behavioral change or on their social media that there are disturbing photos, perhaps bombs or firearms or videos or pictures that are just not right, please make sure law enforcement knows about it."

Earlier in the afternoon Cruz was found alive in Coral Springs, Fla., by a police officer with the Coconut Creek Police Department. He was taken into custody.

Israel also said one AR-15-style rifle was found, along with "multiple magazines."

"Pray for these victims and these families," Israel said.

The suspect allegedly fired shots both outside and inside of the school at varying times, Israel said.

At an earlier press conference Israel said there were 14 victims.

Israel said he had spoken with both President Trump and Florida Gov. Rick Scott.

Trump has offered federal assistance to local law enforcement, according to White House press secretary Sarah Sanders.

The shooting began just before the high school was set to dismiss students for the day, and the school went into lockdown, according to Broward County Public Schools.

Students have since been dismissed.