Eleven people injured in a school shooting in Graz, Austria, on Tuesday are still being treated but are not in life-threatening condition, officials said.

Mass shootings at schools, universities and youth centers remain rare in Europe compared to the US. In recent decades, European governments have tightened gun laws in response to shootings.

A 21-year-old man, Arthur A., committed Austria's deadliest school shooting in Graz, killing 10 before turning the gun on himself. Investigations reveal his introverted nature and obsession with online shooting games.

"I think the first thing is shock, to be honest. I think you can't react the other way. I think everyone in the school is in complete shock," said 24-year-old student Helene Parr, who knows people at the BORG Dreierschützengasse school, where the mass shooting took place.

The victims of Austria's worst school shooting played dead as the raging gunman prowled the corridors, picking off his former classmates and teachers with a legally-owned rifle and pistol.

King Charles and Queen Camilla have sent an emotional message to Austria following the shooting rampage in Graz.