Ten people have been killed in a school shooting in the Austrian city of Graz, police have said.

The incident took place at Dreierschützengasse secondary school in the north-west of the city.

Six females and three males were killed in the attack, according to Interior Minister Gerhard Karner. Police said the 21-year-old gunman took his own life in a school bathroom shortly after.

A further 28 people are being treated for their injuries in hospital, according to local media reports.

The gunman was an Austrian man and former Dreierschützengasse student who didn’t graduate from the school, Karner told a news conference on Tuesday afternoon.

In the same conference, officers confirmed the gunman was not known to police before the attack.

Current information suggests the gunman legally owned the two guns used in the attack and had a firearms licence, police added.

Three days of mourning have been declared in Austria, and a nationwide minute’s silence will be held on Wednesday at 10:00am local time in memory of the victims.