Five people died, including an assailant, and 17 others were wounded in a shooting in the heart of Vienna hours before a coronavirus lockdown started, Austrian authorities said Tuesday. The dead attacker was a 20-year-old Austrian-North Macedonian dual national who had a previous terror conviction.

Two men and two women died from their injuries in the attack Monday evening, Chancellor Sebastian Kurz said. The attacker was 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.

"It is now confirmed that yesterday's attack was clearly an Islamist terror attack," Kurz said. "It was an attack out of hatred — hatred for our fundamental values, hatred for our way of life, hatred for our democracy in which all people have equal rights and dignity."

Interior Minister Karl Nehammer later told APA that the dead assailant, who had roots in the Balkan nation of North Macedonia, had a previous conviction under a law that punishes membership in terrorist organizations.

'Repugnant attack on innocent citizens'

The attacker, named as Kujtim Fejzulai, was sentenced to 22 months in prison in April 2019 because he had tried to travel to Syria to join the Islamic State group. He was granted early release in December under juvenile law.

Fifteen house searches have taken place and several people have been arrested, Nehammer said. The attacker, he said, "was equipped with a fake explosive vest and and an automatic rifle, a handgun and a machete to carry out this repugnant attack on innocent citizens."

Authorities were still trying to determine whether further attackers may be on the run. 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 life-threatening condition.

The shooting began shortly after 8 p.m. local time 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.

Half-empty glasses and cups are seen on a café patio after the shooting. (Leonhard Foeger/Reuters)

Kurz said that "we are victims of a despicable terror attack in the federal capital."

His government on Tuesday ordered three days of official mourning, with flags on public buildings to be flown at half-mast until Thursday, APA reported. A minute of silence was to be held at noon Tuesday.

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 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.

Police officers check a person after the shooting. (Ronald Zak/The Associated Press)

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 spokesperson Steffen Seibert tweeted. "The battle against these murderers and their instigators is our common fight."

U.S. President Donald Trump tweeted Monday night as he prepared for his final rally ahead of election day: 

Egypt's Al-Azhar, the Sunni Muslim world's foremost religious institution, condemned the "terrorist attacks" in Vienna. It called on international institutions "to stand united" against terrorism and reject violence and hatred.

Austria's military has provided 75 soldiers to guard key sites in Vienna, freeing up police to continue the investigation.