At least 9 dead in Austrian school shooting, along with alleged shooter, mayor says

Nine people are dead and 12 are injured after a shooting on Tuesday at a high school in Graz, Austria, the city's mayor said, adding that the alleged shooter is also dead.

Austrian state police confirmed the death toll, after earlier saying on social media that there had been several fatalities at the school, the BORG Dreierschützengasse.

Among the dead were three males and six females, Austrian Interior Minister Gerhard Karner said during a press conference on Tuesday.

At least 12 people were injured, some severely, officials said.

The shooter died by suicide in a bathroom in the school during the incident, a Styria police spokesperson said.

"Today is a day of sorrow and processing the dramatic incident," Styria Gov. Mario Kunasek said at the press conference.

The suspect, a 21-year-old Austrian citizen and former student of the school who never graduated, acted alone, authorities said. The shooter used a long gun and a handgun, that were found at the scene and are now being investigated, a Styria police spokesperson said. The suspect legally owned the two weapons used in the attack, Karner said.

Police had "no prior police records on this individual," Karner said. "There was no prior warning," he added.

"The school shooting in Graz is a national tragedy that has deeply shocked our entire country," Austrian Chancellor Christian Stocker said in a statement posted on social media.

He added, "Young people suddenly ripped from the lives they had ahead of them. There are no words for the pain and grief that all of us -- all of Austria -- are feeling right now."

Officers responded after gunshots were heard at the school, the Styria State Police said in a message posted on social media, later adding, "The school was evacuated and all persons were brought to a safe meeting point." The 300 officers who responded to the scene were able to secure the scene within 17 minutes, a Styria police spokesperson said.

As of Tuesday afternoon, 40 people remain at the scene of the incident and there is support being provided for students and parents, Kunasek said.

Emergency vehicles, including Cobra tactical vehicles, had been deployed to the site, police said. Video shot near the scene showed a street lined with ambulances and other emergency vehicles.

Stocker declared a three-day national period of mourning, with a nationwide moment of silence for the victims at 10 a.m. local time on Wednesday, he said.

The city of Graz sits in southern Austria, in the Styria province. Its the second-largest Austrian city by population, with about 300,000 residents.

This is a developing story. Please check back for updates.

ABC News' Ellie Kaufman contributed to this report.