Tales of heroism are emerging after a mass shooting at a Florida high school on Wednesday left 17 people dead.
Staff at the school have been praised for protecting students as they were forced to hide under desks and in cupboards to avoid being shot.
One teacher was killed while attempting to barricade a classroom door.
Nikolas Cruz, 19, confessed to carrying out the attack at Marjory Stoneman Douglas High School in Parkland and has been charged with 17 counts of murder.
Students have been sharing their stories of the attack - the deadliest US school shooting since 2012 - and how many more people could have lost their lives had not been for a number of brave individuals.
Who are the heroes?
Tributes have been paid to Aaron Feis, an assistant American football coach at the school, who is being hailed a hero for shielding students from bullets.
Mr Feis, who also worked as a security guard at the school, was fatally injured after diving in front of a pupil.
Another teacher, Scott Beigel, was taking a geography class and opened the door to provide students with shelter. He was shot dead by the gunman while trying to lock the door, student Kelsey Friend told US media.
Student breaks down talking to @GStephanopoulos about hero teacher who helped save her life and lost his own. "I'm so thankful that he was there to help everybody who did live." https://t.co/8DL1ThRqYM pic.twitter.com/bZyvbJs8cO— Good Morning America (@GMA) February 15, 2018
David Hogg, 17, said he was in environmental science class when he heard bangs that sounded like a gun.
He described to the BBC how his teacher closed the door but within seconds the fire alarm sounded, causing his class to "instinctively" leave the room.
"We thought it was a drill," Mr Hogg said.
He said he entered a corridor that was filled with a "tsunami" of students before they were all stopped by "a very heroic janitor".
"He said, 'Don't go that way - he [the shooter] is over there'."
Teacher Ashley Kurth told the Daily Beast website she was able to "grab" dozens of children from corridors.
"It was a terrifying experience. After about 60 or 90 seconds, I shut the door and I got everybody back in our storage area and in my office. I think we had like 65 in my room," Ms Kurth said.
Another teacher, Melissa Falkowski, told CNN "she "managed to put 19 kids in the closet with me"", where they remained for 30 minutes until officers arrived.
Jim Gard, who taught mathematics at the school, said he "locked the door, turned out the lights and had the kids go to the back of the room".
"I told the kids to hang in there," he told the Miami Herald.
Who are the other victims?
Chris Hixon was the athletic director at Stoneman Douglas and was reported dead by local media. He had two children of his own.
The students who died were:
- Alyssa Alhadeff, 14
- Martin Duque, 14
- Alaina Petty, 14
- Alex Schachter, 14
- Jaime Guttenberg, 14
- Cara Loughran, 14
- Gina Montalto, 14
- Luke Hoyer, 15
- Peter Wang, 15
- Carmen Schentrup, 16
- Nicholas Dworet, 17
- Joaquin Oliver, 17
- Helena Ramsey, 17
- Meadow Pollack, 18
What is the political fallout?
In an address following the shooting on Thursday, US President Donald Trump did not mention the word "gun" or "firearm" once.
He said he was "committed to working with state and local leaders to help secure our schools and tackle the difficult issue of mental health".
The Florida suspect reportedly sought psychological services at a clinic at some point, and accounts from former classmates paint a picture of a 19-year-old who was a social outcast with violent tendencies.
However, on Friday the White House was refusing to release a photo of Mr Trump signing a law last year that made it easier for people with mental health issues to buy guns.
White House spokeswoman Sarah Sanders, who has received a total of 12 requests for the image from CBS News, said: "We don't plan to release the picture at this time."
The legislation passed by Mr Trump in February last year repealed a rule that required people receiving mental health benefits to be entered into an FBI database.
The president tweeted that he was planning to visit Parkland, Florida, on Friday to "meet with some of the bravest people on Earth". He did say when he was due to arrive.
What do we know about the suspect?
Mr Cruz had been expelled from the school he has confessed to attacking and some students said they had joked "he's the one to shoot up the school".
One former schoolmate, Chad Williams, told Reuters Mr Cruz was an "outcast" who was "crazy about guns".
His interest in weapons was apparent on his social media profiles, which Broward County Sheriff Scott Israel said were "very, very disturbing".
What were the warnings?
After seeing a comment on a YouTube post last year by Mr Cruz, user Ben Bennight contacted the FBI and spoke to representatives for about 20 minutes.
Mr Bennight said the FBI contacted him again following the school shooting in Parkland.
The FBI confirmed on Thursday that they were made aware of the comment, adding that they had conducted "checks" but were unable to identify the person behind it.
Meanwhile, maths teacher Jim Gard told the Miami Herald that school authorities had emailed teachers about Mr Cruz's behavioural problems.
"There were problems with him last year threatening students, and I guess he was asked to leave campus," he said.