Authorities said 17 people were killed Wednesday when gunfire erupted inside a South Florida high school, sending police scrambling across the quiet suburban community as they hunted for the shooter while students and teachers remained barricaded inside.
A dozen people were killed inside the school, Broward County Sheriff Scott Israel told reporters Wednesday evening. Three more died outside, and two others at area hospitals.
The shooting happened shortly before classes were dismissed at Marjory Stoneman Douglas High School in Parkland, northwest of Fort Lauderdale.
Police have took the suspected shooter into custody, the Broward County Sheriff's Office said.
Two law enforcement officials identified the suspect in custody as Nicolas Cruz.
Robert Runcie, the superintendent of Broward County Public Schools, told reporters at the scene that there are "numerous fatalities."
"It is a day you pray every day you don't have to see," Runcie said.
He said officials were not aware of threats made before the incident.
The Broward County Sheriff's Office said there were at least 14 victims in the incident. It was unclear how many had been injured and how many had been killed.
Earlier in the day, Dan Booker, a fire chief from a nearby city, had said that the number of injured could stretch much higher, estimating 20 to 50 victims. Some of those injured are students who were shot, Booker said.
Booker said he was seeking aid from the Coast Guard and other agencies because many victims will need to be transported by helicopter.
Video from the scene showed police surrounding the building and students being quickly marched away from Stoneman Douglas High. News cameras also captured people being wheeled out on stretchers, though their conditions were not immediately clear. A tweet from the school's parent district, Broward County Public Schools, said, "We are receiving word of multiple injuries."
Police from nearby Coral Springs, who were also responding to the incident, urged students and teachers to remain barricaded inside the school. Law enforcement officials said they were clearing students building by building.
The school, which opened in the early 1990s, had more than 3,000 students in the 2015-2016 school year, according to federal data.
Gov. Rick Scott, R, said he had been briefed by the Broward County sheriff, whose agency was leading the response, as well as by the county's school superintendent. President Trump was notified of the shooting, White House deputy press secretary Lindsay Walters said.
"The president has been made aware of the school shooting in Florida. We are monitoring the situation. Our thoughts and prayers are with those affected," Walters said.
The Broward County school system wrote in a message on Twitter that students and staff "heard what sounded like gunfire" close to the school's dismissal time.
"The school immediately went on lockdown but is now dismissing students," the school system wrote. "We are receiving reports of possible multiple injuries."
The Washington Post's Devlin Barrett contributed to this article.