A gunman opened fire inside a high school in Graz, Austria, on Tuesday morning, killing 10 people and injuring several more before taking his own life.

Authorities later confirmed the tenth victim died in the hospital, bringing the total death toll when not including the shooter to 10 in what has become the country’s deadliest mass shooting in the modern era.

The attacker, identified only as a 21-year-old Austrian male and former student of the school, entered the BORG Dreierschützengasse high school shortly after 10 am local time and began shooting in two classrooms, one of which he had previously attended.

Police said the suspect legally owned the weapons used—a pistol and a shotgun—one of which had been recently acquired. His body was later found in a bathroom inside the school, reports the Guardian.

Among the dead were nine students and one teacher. Eleven others were taken to local hospitals for treatment. Authorities confirmed six of those killed at the scene were female and four male. The suspect acted alone, according to Interior Minister Gerhard Karner.

Police launched a large-scale response, including special forces units and helicopters. The building was evacuated and searched, and surrounding streets were sealed off by armed officers. A Red Cross official said 160 emergency responders were deployed.

A nationwide minute of silence is scheduled for 10 am Wednesday as part of a three-day period of mourning announced by Chancellor Christian Stocker, who called the incident “a national tragedy that has shocked us all.”

Austria’s president, Alexander Van der Bellen, said the attack “strikes our country at the heart,” adding that “these were young people who had their whole lives ahead of them.”

Authorities have not released a motive, and officials say no further details will be disclosed at this time out of respect for the families and due to the ongoing investigation.

Though Austria has a high rate of civilian gun ownership, mass shootings remain rare. The last major incident occurred in 2020, when four people were killed in a terrorist attack in Vienna.