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.

This is the first picture of the “drop out” school shooter who killed 10 people in Austria this week in one of the worst act of violence in the country’s history.Identified as Arthur A, the 21-year-old is understood to be a former pupil at the school in the southern city of Graz.

"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.

Austria to observe three days of mourning after a 21-year-old attacker kills at least 10 people at a school in Graz.

Residents of Graz gathered for a mass and a candle lit vigil to mourn the 11 victims who were killed after a former pupil opened fire in a school. View on euronews

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.

The deadliest school shooting in the nation’s recent history has prompted some gun enthusiasts to worry about the prospect of stricter ownership laws.

Not long afterwards in south-east Austria, a 21-year-old who had dropped out of school three years earlier, walked into Dreierschützengasse high school in Graz at 09:43, and shot dead nine students and a teacher with a Glock 19 handgun and a sawn-off shotgun.