A large number of children have been killed and dozens injured in a mass Florida school shooting understood to have been carried out by an ex-student.
1.30pm: That concludes our live rolling coverage of this tragic event. But we'll be continue to cover this story throughout the afternoon with extensive coverage on tonight's 6pm news, detailing just who was the gunman and how the shooting unfolded. Bye for now.
1.20pm: CNN reports this is the fourth high school shooting in the US ...this year.
1.07pm: A man who witnessed the shooter being arrested tells AP what happened: "Michael Nembhard told The Associated Press he was in his garage watching TV news coverage of the shooting when he heard a police officer repeatedly yelling, "get on the ground!" Nembhard says he looked up to see a teenage boy on the ground about 150 yards away with an officer pointing a gun at him. The officer stood over the boy until other officers arrived, handcuffed him and led him away. A federal official who spoke on condition of anonymity identified the suspect as Nicolas Cruz. Authorities say the suspect is a former student about 18 years old.
1.02pm: This, from Broward General North Hospital: "First and foremost, we want to extend our condolences and sympathy for all those people, family members involved in the tragedy today. Through the Broward health system, we received 17 patients at Broward Health North, we received eight patients and one suspect. The suspect was treated and released in police custody. Of our eight patients, we had two mortalities, three in critical condition and three are stable."
12.57pm: News stations are reporting the gunman had been expelled from the Marjory Stoneman Douglas High School for disciplinary reasons.
12.54pm: CNN reporter recounts story told by female freshman who survived the shooting: "I just heard banging coming up the hallways. He got to the window. He shot out the window of the classroom. He just kept going and she said at that point, she started to hear people screaming, 'Help me'. She said one of the teachers grabbed some jackets and other articles of clothing to go and try help to stop bleeding, to try and use articles of clothing to stop… to help with wounds. She said when that teacher came back, she was absolutely covered in blood. She said there was just so much blood. There was enough injury, there was blood everywhere and people needing help."
12.43pm: Sheriff Scott Israel: "We have 17 confirmed victims. 12 victims were within the building. Two victims were just outside the building. One victim is on the street at the corner of Pine Island and two folks are… People lost their lives at the hospital."
12.41pm: Parkland (where the shooting took place) with a population of 31,000, was named Florida’s safest city last year.
12.39pm: An emotional Sheriff Scott Israel: "We had countless magazines – multiple magazines – and at this point, we believe he had one AR-15 rifle."
12.35pm: Rosa Flores, CNN reporter: "I was talking to one parent who was telling me that she was getting messages like, 'I love you' from her daughters. Very intense moments as these parents tried to figure out what is happening inside the school and administrators, also, trying to let parents know what was happening and of course, at this hour, investigators scouring through that school. That's one of the things that a lot of the time, we don’t think about."
12.28pm: The five most deadly US school/University shootings (excluding today):
1. Virginia Tech, 2007, 33 killed, 25 injured
2. Sandy Hook, December 14, 2012, 27 Killed
3. UT Austin, 1966, 17 killed, 31 injured
4. Columbine High School Massacre, April 20, 1999, 13 people died, 24 injured
5. Umpqua Community College Shooting 2015, 10 dead, 9 injured.
12.27pm: The death toll has been revised to 17.
12.24pm: If you're just joining us, this is 19-year-old thought to be behind today's deadly shooting on his old school.
12.22pm: Sandy Hook, in Connecticut, remains America's worst school shooting with 20 six and seven-year-olds shot dead by 20-year-old Adam Lanza.
12.18pm: We are continuing with our live updates. CNN is reporting 16 dead in the Marjory Stoneman Douglas High School shooting today.
That tops the Columbine High School disaster in 1999, which was 15, including the two shooters.
11.35am: That concludes our live coverage of this morning's tragic mass shooting at Marjory Stoneman Douglas High School in Parkland, Florida. As things stand, at least 14 have been taken to hospital, at least two dead, many more injured. The shooter has been arrested, he's thought to be an ex-student around 18-years old. That's all for now. Thanks for following us.
11.33am: More from Sheriff Scott Israel: "We have a shooter in custody. He was taken into custody, I believe about an hour after he left Stoneman Douglas, after he committed this horrific, homicidal, detestable act. The FBI and our crime scene people will be investigating this horrific scene as soon as the buildings are clear. Right now, the buildings are not safe enough to be cleared."
11.31am: Sheriff Scott Israel: "I wanna start out by saying this is an unbelievably catastrophic day in Broward County history. It's devastating.
"I'm sick to my stomach. We have multiple casualties. We’ve had approximately 14 people transported to hospitals with varying degrees of injuries. There are multiple casualties.
"It's a fluid scene right now. We have multiple SWAT teams clearing all the buildings.
"If anybody knows anything about Stoneman Douglas High School, it's one of the biggest schools in Broward County, it's a huge campus, so we have multiple SWAT teams to make sure there are no other shooters."
11.25am: More from Zackary Wells: "I did not know him personally, I had seen him before, but had not really talked to him or known him at all.
"One of my friends said that he used to follow him on social media accounts where he would regularly post videos of him with guns and knives and things like that.
"Yes, he was a former student. One of my teachers said something about him either transferring or being kicked out of the school, I’m not sure which it was but yes, he did used to go to our school."
11.18am: Zackary Wells continued: "Yes, I know who it was.
"We got a picture of him and we were actually just sending it around to different officers and whatever, what contacts we had to get the photo out to them so they could get him apprehended fairly quick. We don't have a picture of him with the gun in his hand, we have a picture of him as a… a composite photo of a previous year that he was in from school."
"One of the kids in that class, good friends him, was on the phone with police officers and they gave information of his name and we looked for his name in a book and found a picture of him in a school composite photo.
11.15am: This from Zackary Wells, eye witness: "I believe it stayed in that area, and then he, from what I heard, he dropped his rifle and he made his way out with the other students that were being evacuated. He walked on over to Windham Lake and he was accosted a quarter mile from my area."
11.12am: Heart-wrenching photos taken by AP might be the best illustration of the personal toll from this tragedy.
11.03am: Broward County Florida Sheriff Scott Israel has just held a press conference. Among the main points:
**Multiple causalities, 14 taken to hospital
**The shooter was approximately 18-years-old, he was found off campus, he was taken without confrontation. "There was a time he did attend the school."
10.58am: From Victor Oquendo, ABC News reporter: "Police have said that the shooter is in custody and our affiliate, WLPG, is also reporting that they’ve taken in a family member, possibly a sibling, in for questioning as well."
10.56am: The shooting suspect, thought to be an ex-student of the Florida high school, has been led away in cuffs. This video shows how it happened.
10.52am: Broward County Public Schools Superintendent Robert Runcie has told CNN he was returning from presenting the district's Teacher of the Year with a brand new car when he got the news.
"Today has been a day of enormous mountains and valleys," he said.
"We were giving the teacher of the year keys to a brand new Toyota Camry," he told CNN. "We were celebrating our teachers, our schools and I got in the car, and as I'm driving back to the office, I start seeing communication and I hear from staff that we may have a tragedy."
10.46am: Parent John Obin has told AP his son, a freshman at the South Florida high school was in class when he heard several shots.
The father says his son advised that teachers quickly rushed students out of the school.
He adds the boy told his father that he walked by two people on the ground motionless - and apparently dead - as students rushed outside.
"This is a really good school, and now it's like a war zone," Obin said.
10.40am: Superintendent of Broward School District Robert Runcie, speaking to media, said there were fatalities but could not confirm number; believes shooter to be former student; "every day I get up, this is something I pray I will never have to see."
10.35am: Listte Rozenblat, mother of high school student: “My daughter texted us sometime around 2:30 or so. I had unfortunately missed a call and a text. She texted my husband and she said there was a shooter in the school. He told her to remain calm and everything’s going to be fine. We called the school to verify the account and unfortunately, it was confirmed, so he just took off in the car but he couldn’t get in – he couldn’t get through the school."
10.27am: "At this point, we have no evidence that there's been more than one shooter. The individual, again, we believe has been apprehended," said Superintendent of the local school district to the Sherriff's office.
"I believe there's an administrator teacher that was involved, maybe more. I can't confirm if that's one of the fatalities at the moment."
10.25am: Several people from the school are now tweeting that they're being let out of the school, that they're okay. That being said, Florida senator Bill Nelson reports there are "many deaths, many fatalities". One person confirmed dead from one eye witness, at least two others dead." – ABC News
10.17am: Local Senator Bill Nelson says "this is a bad day," adding that there are a "number of fatalities" in this shooting.
10.15am: Steve Gomez, Special FBI agent has told the ABC: "Well, if that is one of the suspects, they're clearly doing a fast investigation on that individual, because they're going to try and judge, does he have associates? And is that the only shooter that was involved? So interviewing all of the students and faculty who may have heard or seen what has occurred will be essential to try and figure out was it one shooter, more than one, what type of weapons and so on.
10.11am: Multiple sources reporting gunman is now in custody.
10.05am: News ABC reports: "We know it's just one shooter.
"They may have someone in custody and it may just be one student, but until you know that, you’re going to treat it as unresolved>"
10.02am: This from AP: "Len Murray's 17-year-old son, a junior at the South Florida high school where shooting was reported, sent his parents a chilling text: "Mom and Dad, there have been shots fired on campus at school.
"There are police sirens outside. I'm in the auditorium and the doors are locked."
Those words came at 2:30 pm Wednesday. A few minutes later, he texted again: "I'm fine."
Murray raced to the school only to be stopped by authorities under a highway overpass within view of the school buildings in Parkland.
No information was immediately given to parents, Len Murray says.
And he says he remained worried for all those inside.
"I'm scared for the other parents here. You can see the concern in everybody's faces. Everybody is asking, 'Have you hard from your child yet?'"
9.58am: A CBS reporter is saying the gunman has been caught. Not confirmed by authorities at this stage.
9.52: Donald Trump weighing in...
9.50am: One person is reportedly dead, according to the Miami Herald.
9.47am: A student has told news site WSVN they thought there was a fire drill: "But then word started going around that it was shots and not just like something else, everyone just started running towards the canal."
9.43am: "All of a sudden there was a really loud noise…..people are crying the closet," a student texted newssite CBS4's Rick Folbaum.
CBS4 reported the school was in lockdown from 3pm (local time), but some students were walking out of the school with their hands in the air.
The Margate Fire Department estimate 20 to 50 people may be injured.
White House Deputy Press Secretary Lindsay Walters said: "We are moitoring the situation. Our thoughts and prayers are with those affected."
9.38am: A witness outside the school says there is a “steady steam” of police going into the school.
9.35am: The incident happened at aaround 2.40pm, local time, as kids were leaving Marjory Stoneman Douglas High School.
9.30am: Authorities say they're responding to a shooting at a Florida high school and the school has been locked down.
At least 20 people appear to have been injured, according to reports from CNN and Fox.
The shooting was said to have happened as children were leaving the school.
President Trump has been briefed on the incident.
The shooter is still at large, reports Florida news outlet KKTV 11.
The Broward Sheriff's Office has told news outlets the shooting happened at Marjory Stoneman Douglas High School in Parkland.
It wasn't immediately clear how many people were wounded.
Coral Springs Police said on their Twitter account that the school is locked down and that students and teachers inside should remain barricaded until police reach them.
TV footage showed at least one person being wheeled to an ambulance on a gurney while emergency workers appeared to be helping others on the sidewalk. The news broadcasts also showed students running across the street.
More to come.