A teacher who died trying to protect students was among the 17 people killed at a Florida school shooting, a survivor has said.

Geography instructor Scott Beigel had unlocked the door to his classroom to try and let in students who were fleeing from a rampaging gunman, according to a student, but was shot down before he could close and re-lock the door.

As students and staff at Marjory Stoneman Douglas High School have begun processing the brutal aftermath, many are hailing Mr Beigel's sacrifice.

“Mr Beigel was my hero and he still will forever be my hero. I will never forget the actions that he took for me and for fellow students in the classroom,” student Kelsey Friend told CNN as she disintegrated into tears.

Ms Friend said she was “100 per cent certain” that the teacher saved her life.

“If his family is watching this,” Ms Friend said, “please know that your son or brother was an amazing person and I am alive today because of him”.

Florida shooting – in pictures Show all 10 1 /10 Florida shooting – in pictures Florida shooting – in pictures Police arrest a suspect in connection with the shooting at the Marjory Stoneman Douglas High School in Parkland, Florida Reuters Florida shooting – in pictures Parents wait for news after reports of a shooting at Marjory Stoneman Douglas High School in Parkland, Florida AP Florida shooting – in pictures Anxious family members wait for news of students AP Photo/Wilfredo Lee Florida shooting – in pictures Students being evacuated from the school AP Florida shooting – in pictures Students being evacuated from the school Getty Florida shooting – in pictures People gather waiting for word from students AP Florida shooting – in pictures Parents waiting for news on their children AP Florida shooting – in pictures People gather at a hotel where students were taken after the shooting Getty Florida shooting – in pictures Florida Governor Rick Scott speaks to the media as he visits Marjory Stoneman Douglas High School following the shooting AFP/Getty Florida shooting – in pictures Dr. Igor Nichiporenko, Medical Director Trauma, left, and Dr. Evan Boyer, Medical Director, Emergency Services, speak about treating victims and the suspect at a press conference outside Broward Health North hospital AP

Powerful tributes flowed from people who had attended or worked at a summer camp where Mr Beigel worked as a counselor.

Students also shared their grief and their memories of Mr Beigel.

Survivors and school officials are also hailing a football coach, named Aaron Feis, who placed his body between students and the hail of bullets. His death was confirmed by the football team.