Austrian Interior Minister Karl Nehammer told reporters that two men and two women have died from their injuries.
A suspected attacker who was carrying an assault rifle and a fake suicide vest was also shot and killed by police. Authorities are trying to work out whether further attackers may be on the run.
Here is what we know so far about the attack.
When and where did it happen?
The shooting began in the evening on Monday, November 2, near Vienna’s main synagogue as many people were enjoying a last night of open restaurants and bars before the start of a coronavirus lockdown.
Vienna police said several shots were fired shortly after 8pm local time in a city centre street, and that there were six different shooting locations.
Austrian Chancellor Sebastian Kurz said there were believed to have been several gunmen involved in a “prepared” attack.
Rabbi Schlomo Hofmeister said he saw at least one person shoot at people sitting outside bars in the street below his window near the city’s main synagogue.
“They were shooting at least 100 rounds just outside our building,” he said. “All these bars have tables outside. This evening is the last evening before the lockdown.”
How many people were killed?
Two men and two women were killed in the shooting. A suspected attacker was also shot and killed by police.
Fifteen people were injured in the attack in the centre of the capital, among them a police officer. The 28-year-old officer is in hospital but no longer in a life-threatening condition.
Are there any suspects?
Austrian Interior Minister Karl Nehammer said the attacker who was dead, “sympathised with the militant terrorist group IS”. He declined to elaborate, citing the ongoing investigation.
Authorities are still trying to determine whether further attackers may be on the run and people in Vienna have been urged to stay at home on Tuesday.
“We are victims of a despicable terror attack in the federal capital that is still ongoing,” said Austrian Chancellor Sebastian Kurz.
Austria’s military has provided soldiers to guard key sites in Vienna, freeing up police to continue the investigation. Germany and Hungary have offered to send tactical police units to support their Austrian colleagues.
The attack drew swift condemnation and assurances of support from leaders around Europe, including from French President Emmanuel Macron, whose country also experienced three Islamist attacks in recent weeks.
US President Donald Trump tweeted as he prepared for his final rally ahead of election day: “Our prayers are with the people of Vienna after yet another vile act of terrorism in Europe.”