Supported by The victims’ names and ages have not been released. The police said the gunman also died, in an apparent suicide. The attack in the city of Graz was among the worst school shootings in Europe in years. By Christopher F. Schuetze and Jim Tankersley Reporting from Berlin A former student at an Austrian high school opened fire on the campus on Tuesday and killed nine people before apparently killing himself, a rare and shocking episode of the sort of gun violence that is far more common in the United States than in Europe. The killings in Graz, a wealthy university town that is Austria’s second largest city, were among the worst European school shootings in years. It was the deadliest such attack in memory at an Austrian school, and it profoundly rattled the small Alpine nation. The Austrian chancellor, Christian Stocker, cleared his schedule to travel to Graz and declared three days of national mourning. Mr. Stocker, said in a post on social media that “The shooting rampage at a school in Graz is a national tragedy that has deeply shaken our entire country.” State police said the gunman was a 21-year-old who had previously attended the school, BORG Dreierschützengasse, but never graduated. He killed six females and three males on campus, whom the police did not publicly identify. Authorities said they would not release more information on the victims, including how many of them were students, until preliminary investigations had finished. The shooter was found dead in a school bathroom. The police said he had arrived at the school carrying a pistol and a longer gun — they did not clarify whether it was a shotgun or a rifle — that he had legally bought. Officers recovered the weapon on Tuesday. Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times. Thank you for your patience while we verify access. Already a subscriber? Log in. Want all of The Times? Subscribe.