Interior Minister Karl Nehammer said two men and two women have died from their injuries in the attack Monday evening. A suspected attacker, who was carrying an assault rifle and a fake suicide vest, was also shot and killed by police.

Vienna's hospital service said seven people were in life-threatening condition Tuesday after the attack, the Austrian news agency APA reported. In total, 17 people were being treated in hospitals, with gunshot wounds but also cuts. Nehammer said that initial investigations indicate the suspect who was killed had sympathized with the Islamic State group. Police searched his apartment and other premises as well, APA reported.

“We experienced an attack last night by at least one Islamist terrorist,” Nehammer told reporters. He declined to elaborate, citing the ongoing investigation. Authorities were still trying to determine whether further attackers may be on the run, he said. People in Vienna were urged to stay at home if possible on Tuesday and children did not have to go to school. Some 1,000 police officers were on duty in Vienna on Tuesday morning.

Among those wounded in the attack was a police officer, said Nehammer. The 28-year-old officer was in the hospital but was no longer in a life-threatening condition. The shooting began shortly after 8 p.m. (1900 GMT) Monday near Vienna’s main synagogue as many people were enjoying a last night of open restaurants and bars before a month-long coronavirus lockdown, which started at midnight.

Vienna police chief Gerhard Puerstl said the attacker was killed at 8:09 p.m. Chancellor Sebastian Kurz said that “we are victims of a despicable terror attack in the federal capital." Unverified footage posted on social media showed a gunman walking through the streets, apparently shooting at people at random, wounding several. It was unclear whether the person seen shooting was the same individual in each video.

Rabbi Schlomo Hofmeister said he saw at least one person shoot at people sitting outside at bars in the street below his window near the city's main synagogue. “They were shooting at least 100 rounds just outside our building,” Hofmeister said. "All these bars have tables outside. This evening is the last evening before the lockdown.” Authorities said residents have uploaded 20,000 videos of the attack to police.

The attack drew swift condemnation and assurances of support from leaders around Europe, including from French President Emmanuel Macron, whose country has experienced three Islamist attacks in recent weeks, and German Chancellor Angela Merkel. “The Islamist terror is our common enemy,” Merkel spokesman Steffen Seibert tweeted. “The battle against these murderers and their instigators is our common fight.” US President Donald Trump tweeted Monday night 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,” Trump added. 

“The U.S. stands with Austria, France, and all of Europe in the fight against terrorists, including radical Islamic terrorists.” Austria's military has provided 75 soldiers to guard key sites in Vienna, freeing up police to continue the investigation. Germany and Hungary have also offered to send tactical police units to support their Austrian colleagues.