A fourth person has died in a suspected terror attack in Austria, officials have confirmed.
A gunman opened fire near one of Vienna's main synagogues on Monday evening.
Rabbi Schlomo Hofmeister said he saw at least one person shoot at people sitting outside bars in the street below his window.
"They were shooting at least 100 rounds just outside our building," he said.
Austrian Interior Minister Karl Nehammer told reporters that two men and two woman have died from their injuries.
A suspected attacker, who was carrying an assault rifle and a fake suicide vest, has also been shot and killed by police.
Mr Nehammer told reporters that "the attacker sympathised with the militant terrorist group IS".
"We are victims of a despicable terror attack in the federal capital that is still ongoing," said Austrian Chancellor Sebastian Kurz.
A total of 15 people, including a police officer, were injured in the attack.
The 28-year-old officer is in hospital but no longer in a life-threatening condition.
Authorities are trying to determine whether more attackers may be on the run.
Residents in the city are being urged to stay at home today (Tuesday).
Leaders across Europe offered their support to Austria following the attack.
Among those was 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."
"These evil attacks against innocent people must stop," Mr Trump added.
"The US stands with Austria, France, and all of Europe in the fight against terrorists, including radical Islamic terrorists."
Soldiers have been deployed 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.
