An American teacher who was shot while tackling and disarming a student inside his classroom said on Monday that his swift decisions "were the only acceptable actions" to save his seventh-grade students.

Jason Seaman, speaking publicly for the first time since the shooting in suburban Indianapolis on Friday, thanked the local community for its support and stressed that he wanted the focus to be on the other person shot during the incident: 13-year-old student Ella Whistler, who was seriously wounded.

"Her courage and strength at such a young age is nothing short of remarkable," Mr Seaman said during a news conference at the school district's administrative building. "We all should continue to keep her in our minds as she continues to recover."

School officials said Ella was improving and making progress while recovering at an Indianapolis hospital. Her family has said she was in critical but stable condition following the shooting, though no other details about her injuries have been released.

Mr Seaman is credited with stopping an armed student who entered his classroom at Noblesville West Middle School. Witnesses said the 29-year-old former college football player ran toward bullets as he tackled the student. The teacher was shot three times, according to his brother.