VIENNA — A gunman killed at least nine people at a secondary school in the southern Austrian city of Graz on Tuesday, in the worst school shooting in the country's modern history.

Police said the attacker also died and that they were working on the assumption that he had operated alone. National broadcaster ORF said about 30 people were wounded.

There were six female and three male victims, Interior Minister Gerhard Karner said in a news conference in Graz.

The 21-year-old sole suspect was a pupil at the school but did not graduate, Karner said.

Austrian Chancellor Christian Stocker declared three days of national mourning on Tuesday.

All of Austria will remember the victims, Stocker told a news conference.

"This is a dark day," he said, adding that the Alpine country had seen "an act of unimaginable violence".

A local police spokesman said the area had been secured, the school had been evacuated and relatives of the victims and pupils were being cared for.

The Salzburger Nachrichten newspaper said the suspect was Austrian, believed to have had no criminal record, and that he had recently purchased one of the weapons.

It said the gunman had been a victim of bullying. He carried a pistol and a shotgun and opened fire on pupils in two classrooms, one of which had once been his own.

Police were called to the scene at around 10 am after shots were heard at the school.

Julia Ebner, an extremism expert at the Institute for Strategic Dialogue think tank, said the incident appeared to be the worst school shooting in Austria's postwar history, describing such shootings as rare compared to some countries including the United States.

European Union foreign policy chief Kaja Kallas said on X: "Every child should feel safe at school and be able to learn free from fear and violence. My thoughts are with the victims, their families and the Austrian people in this dark moment."

Austria has one of the most heavily armed civilian populations in Europe, with an estimated 30 firearms per 100 persons, according to the Small Arms Survey, an independent research project.

Machine guns and pump action guns are banned, while revolvers, pistols and semi-automatic weapons are allowed only with official authorization.

Agencies via Xinhua