A former student killed 10 people and himself at a secondary school in Austria's second-largest city, Graz, on Tuesday in the worst school shooting in Austria's modern history.

Interior Minister Gerhard Karner said six of those killed at the school were female and three were male, without giving any details of their ages. Graz Hospital later confirmed the death of a 10th person.

Karner said another dozen people had been injured but gave no further details about the victims. Austrian media said most were students.