A former student shot and killed ten people at a school in Austria's second-largest city on Tuesday. He also injured twelve other people before killing himself, according to officials.

Police said they don't know why the 21-year-old man did it, and he had no criminal history. He used two weapons that police believe he owned legally.

Austrian Chancellor Christian Stocker told reporters in Graz, a city of about 300,000 people in southeastern Austria, that today is a very sad day for their country.

He called it "a national tragedy that deeply shocks us" and announced three days of national mourning. During this time, the Austrian flag would be lowered to half-mast at official buildings. Also, a national minute of silence was planned for Wednesday morning to remember the victims.

Special police units were sent to BORG Dreierschützengasse high school, which is about one kilometer from Graz's city center. This happened after calls at 10 a.m. reported that shots had been fired. More than 300 police officers went to the school, and everyone was evacuated. Videos from the scene showed students quickly leaving the building past police officers carrying guns.

Police confirmed that order was restored within 17 minutes.

Police said the attacker was a 21-year-old Austrian man who lived near Graz and acted alone. His name was not released.

Local police chief Gerald Ortner said that two guns, a rifle and a pistol, were used in the shooting and found at the scene. He also said that the person who did the shooting seemed to own them legally. The man then killed himself in a bathroom.

Interior Minister Gerhard Karner said the shooter used to be a student at the school but did not finish his studies there. He also said he could not give details about when the man left the school or how old he was.

On Tuesday afternoon, Karner said that six women and three men had died, but he didn't give more information. He also said that twelve people were hurt. Later, the Austria Press Agency reported that a woman had died from her injuries in the Graz state hospital, making the total number of deaths ten.

The Austrian Red Cross sent 65 ambulances and 158 emergency workers to the place where the accident happened to help the injured. Also, 40 trained psychologists gave support to students and parents. The Red Cross asked local people to donate blood.

Metin Özden, who owns a kebab restaurant close to the school, noticed police cars rushing past, followed by a helicopter overhead. He told the Krone newspaper, "I realised something terrible must have occurred. I've never witnessed so many emergency services before." He also told the paper he saw parents walking by his restaurant, crying as they headed towards the school.

Tuesday's attack was probably the most serious one in Austria since World War II.

In 2020, four people were killed in Vienna, and the attacker, who supported the Islamic State group, also died in a shooting. More than 20 other people were injured, including a police officer.

In June 2015, a man drove an SUV into a crowd in Graz city centre, killing three people and injuring over thirty others.

Austria has a strong hunting tradition, and its gun laws are quite relaxed compared to other countries in the European Union.

In Austria, if you are 18 or older, you can buy some weapons like rifles and shotguns that you load by hand after each shot, without needing a special permit. Gun shops just need to make sure the buyer is allowed to own weapons and then register the weapon.

Getting other weapons, like repeating shotguns or semi-automatic guns, is harder – you need a gun ownership card and a firearms permit.