A lone gunman brought terror to a Florida high school minutes before the end of classes on Wednesday, killing at least 17 people and wounding many more in a frantic flurry of gun fire.
Pupils raced for safety as panic spread through Marjory Stoneman Douglas High School, about 15 miles west of Fort Lauderdale.
The death toll makes it the second worst mass school shooting in American history, after the Sandy Hook attack in 2012 when 26 people died.
Disturbing cellphone footage of students huddling in a classroom captured the sound of at least 20 gunshots fired in short bursts over a matter of seconds.
Swat teams scrambled to the scene in an armoured personnel carrier.
Within an hour police said they had detained a suspect, whom they later identified as Nikolas Cruz, a 19-year-old former pupil who had been expelled for disciplinary reasons.
One teacher said he had previously been identified as a threat and was not allowed to return to the school if he was carrying a backpack.
Scott Israel, Broward County Sheriff, said 12 people were found dead inside the school, two died outside, one was killed in the street and two more died in hospital.
He said the gunman had been armed with an AR-15 style assault rifle and carried multiple magazines.
He added that investigators were probing his social media presence looking for a motive.
“We have already begun to dissect his websites and the social media that he was on,” he said. “Some of the things that have come to mind are very, very disturbing.”
Hospital staff said at least three casualties were in a critical condition on Wednesday evening.
The shooting was the latest in a deadly series of attacks at schools across America. The campaign group Everytown for Gun Safety has recorded 18 school shootings already this year and says incidents have averaged one a week since 2013.
A 15-year-old gunman killed two students at a high school in Kentucky last month.
Local education officials in Broward County said they had no warning that an attack was imminent.
Nicole Baltzer, 18, said she was in a trigonometry class when the fire alarm sounded. As students began leaving classrooms, she continued, gunshots sent everyone into a panic.
“I heard so many gunshots, at least like six. They were very close,” she said.
Pupils were seen streaming out of the building with their hands in the air as armed officers hunted for the gunman. Some ran, others walked in single file with their hands on the shoulder of the pupil in front of them.
Parents raced to the school to check on the safety of their children.
John Obin said his son described seeing two people lying on the ground motionless – apparently dead – as the premises were evacuated.
“This is a really good school, and now it’s like a war zone,” he said.
One teacher described how Cruz had previously been identified as a threat.
"We were told last year that he wasn't allowed on campus with a backpack on him," Jim Gard, a maths teacher, told the Miami Herald. "There were problems with him last year threatening students, and I guess he was asked to leave campus."
Robert Runcie, superintendent of Broward Schools, asked for prayers.
“It’s a day that you pray every day when you get up that you will never have to see. It is in front of us,” he told WSVN Channel 7.
The White House cancelled its planned news briefing and officials said President Donald Trump was being kept abreast of developments.
“My prayers and condolences to the families of the victims of the terrible Florida shooting,” he said on Twitter. “No child, teacher or anyone else should ever feel unsafe in an American school.”
Schools have been frequent targets and hold drills on what to do in the event of an “active shooter”.
The attack will raise fresh questions about the ready availability of guns and whether schools can do more to protect pupils. The AR-15 rifle, in particular, is frequently implicated in mass shootings, including notorious attacks in Sandy Hook, Aurora, San Bernardino and many more.
Iain Overton, director of Action on Armed Violence and author of Gun Baby Gun, said both Left and Right were guilty of pushing superficial solutions to making schools safer, whether offering technological fixes such as bulletproof blankets for pupils or suggesting that teachers should be armed in order to deter or immobilise attackers.
“Both approaches are doomed to fail in a country where guns are ubiquitous and background checks flimsy,” he said.
“The only thing to make American schools safer is to address the entire epidemic of gun violence across the US at its root: by amending the Second Amendment. Anything less is a false promise.”
The Second Amendment guarantees the right of Americans to bear arms and is cited by opponents of tougher gun control.
Three of the 10 deadliest mass shootings in modern US history have happened in the past four months. In October, Stephen Paddock killed 58 people when he opened fire on a crowd of 22,000 people at a concert in Las Vegas from his hotel room window.
Previous gun attacks
- Nov 5 2017: Devin Patrick Kelley opened fire inside the First Baptist Church in Sutherland Springs, Texas, killing 26 members of the congregation and wounding 20 more. The toll made it the deadliest attack on a place of worship in US history. Kelley died after a high-speed car chase and had suffered multiple gunshot wounds.
- Oct 1, 2017: A gunman identified by authorities as Stephen Paddock opened fire on an outdoor music festival on the Las Vegas Strip from the 32nd floor of a hotel-casino, killing 58 people and wounding more than 500. SWAT teams with explosives then stormed his room and found he had killed himself.
- Jun 12, 2016: Gunman Omar Mateen opened fire at an Orlando, Florida, nightclub, killing 49 people. Mateen was later killed in a shootout with police.
- Feb 25, 2016: Cedric Ford, 38, killed three people and wounded 14 others at a lawnmower factory where he worked in the central Kansas community of Hesston. The local police chief killed him during a shootout with 200 to 300 workers still in the building, authorities said.
- Feb 20, 2016: Jason Dalton, 45, is accused of randomly shooting and killing six people and severely wounding two others during a series of attacks over several hours in the Kalamazoo, Michigan, area. Authorities say he paused between shootings to make money as an Uber driver. He faces murder and attempted-murder charges.
- Dec 2, 2015: Syed Rizwan Farook, 28, and Tashfeen Malik, 27, opened fire at a social services center in San Bernardino, California, killing 14 people and wounding more than 20. They fled the scene but died hours later in a shootout with police.
- Oct 1, 2015: A shooting at Umpqua Community College in Roseburg, Oregon, left 10 people dead and seven wounded. Shooter Christopher Harper-Mercer, 26, exchanged gunfire with police, then killed himself.
- Jun 17, 2015: Dylann Roof, 21, shot and killed nine African-American church members during a Bible study group inside the Emanuel African Methodist Episcopal Church in Charleston, South Carolina. Police contend the attack was racially motivated. Roof has been sentenced to death in the shootings.
- May 23, 2014: A community college student, Elliot Rodger, 22, killed six people and wounded 13 in shooting and stabbing attacks in the area near the University of California, Santa Barbara, campus. Authorities said he apparently shot himself to death after a gunbattle with deputies.
- Sept 16, 2013: Aaron Alexis, a mentally disturbed civilian contractor, shot 12 people to death at the Washington Navy Yard before he was killed in a police shootout.
- July 26, 2013: Pedro Vargas, 42, went on a shooting rampage at his Hialeah, Florida, apartment building, gunning down six people before officers fatally shot him.
- Dec 14, 2012: In Newtown, Connecticut, an armed 20-year-old man entered Sandy Hook Elementary School and used a semi-automatic rifle to kill 26 people, including 20 first-graders and six adult school staff members. He then killed himself.
- Sept 27, 2012: In Minnesota's deadliest workplace rampage, Andrew Engeldinger, who had just been fired, pulled a gun and fatally shot six people, including the company's founder. He also wounded two others at Accent Signage Systems in Minneapolis before taking his own life.
- Aug 5, 2012: In Oak Creek, Wisconsin, 40-year-old gunman Wade Michael Page killed six worshippers at a Sikh Temple before killing himself.
- July 20, 2012: James Holmes, 27, fatally shot 12 people and injured 70 in an Aurora, Colorado, movie theater. He was sentenced to life in prison without parole.
- Apr 2, 2012: Seven people were killed and three were wounded when a 43-year-old former student opened fire at Oikos University in Oakland, California. One Goh was charged with seven counts of murder and three counts of attempted murder, but psychiatric evaluations concluded he suffered from long-term paranoid schizophrenia and was unfit to stand trial.