A 19-year-old gunman opened fire Wednesday at a Florida high school he had previously been expelled from, killing at least 17 people and injuring more than 14 before he was arrested, authorities said.
The violence erupted shortly before dismissal at Marjory Stoneman Douglas High School in Parkland, about 45 miles north of Miami. Live television footage showed students streaming out of the building as dozens of police and emergency services personnel swarmed the area, Reuters reports.
The gunman was identified as Nikolas Cruz, who previously attended the school and was expelled for unspecified disciplinary reasons, Broward County Sheriff Scott Israel said at a news briefing hours later. The gunman surrendered to police without a struggle.
"There are numerous fatalities. It's a horrific situation," Broward Country Schools Superintendent Robert Runcie told reporters. "It's catastrophic. There really are no words."
The school district had no warning of a potential shooter and there was no evidence of more than one shooter, Runcie said.
Twelve of the dead were killed inside the school building; two others just outside; one more on the street, and two other victims died of their injuries at a hospital, Israel said. He said the victims comprised a mixture of students and adults.
It was the 18th shooting in a U.S. school so far this year, according to gun control group Everytown for Gun Safety. That tally includes suicides and incidents when no one was injured, as well as the January incident when a 15-year-old gunman killed two students at a Benton, Kentucky, high school.
McKenzie Hartley, 19, who identified herself as the sister of a student at the school described Wednesday's scene in a text message to Reuters: "She heard him shooting through the windows of classrooms and two students were shot."
Lissette Rozenblat, whose daughter goes to the school, told CNN: "It is just absolutely horrifying. I can't believe this is happening." Her daughter called to say she was safe but had heard the cries of a person who was shot.
"She was very nervous. She said that she could hear the person who was shot crying out for help. My daughter is safe and I am very grateful."
Live television showed dozens of students, weaving their way between law enforcement officers with heavy weapons and helmets, and large numbers of emergency vehicles including police cars, ambulances and fire trucks.
The school had recently held a meeting to discuss what to do in the event of such an attack, 15-year-old freshman Ryan Gott told CNN.