Austria has declared three days of national mourning following what appears to be the deadliest attack in its post-World War II history.

Officials in Austria say a school shooting has left at least 10 people dead in the European nation's second-largest city, Graz. The shooter is also dead.

The 21-year-old man suspected of this week carrying out Austria's worst school shooting was likely an introverted fan of online shooting games, criminal investigators said on Thursday. The Austrian man,

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.

Videos from social media show the moment loud gunshots were heard in a classroom, during a deadly school shooting in Graz, Austria. Footage shows people panicking and looking outside through a window, as gunshots ring out in the background. Other footage shows armed police officers inside school corridors as pupils run towards the exit.