A police car patrols in front of the Vienna Opera House with the inscription reading "Mute", following gunfire in the city center of Vienna, Austria, early Nov 3, 2020. (RONALD ZAK/AP)

VIENNA - Austrian police have arrested 14 people linked to the main suspect in the Vienna attack, Interior Minister Karl Nehammer said at a news conference on Tuesday.

A 20-year-old Austrian-North Macedonian dual citizen, shot by police at the scene, is the chief suspect in the attack which left four dead and 22 injured. Officers raided 18 residences in their investigations.

This is not a conflict between Christians and Muslims or between Austrians and migrants. No, this is a fight between the many people who believe in peace and the few (who oppose it). It is a fight between civilization and barbarism.

Sebastian Kurz,

Austrian Chancellor

Authorities identified the primary suspect as a convicted jihadist, and said they could not rule out the possibility that other shooters were still on the loose.

Chancellor Sebastian Kurz pledged in a televised address to “hunt down the perpetrators and those who stand behind them”.

An elderly man and woman, a young passer-by and a waitress had been killed in cold blood, and some of the 14 wounded victims were fighting for their lives, he said.

“The attack yesterday was clearly an Islamic terror attack,” Kurz added. “This is not a conflict between Christians and Muslims or between Austrians and migrants. No, this is a fight between the many people who believe in peace and the few (who oppose it). It is a fight between civilization and barbarism.”

The attacker shot dead by police was identified by Nehammer as 20-year-old Kujtim Fejzulai.

The interior ministry said Fejzulai had been sentenced to 22 months in jail in April 2019 for attempting to travel to Syria to join Islamic State, and had been released early in December.

Nehammer said Fejzulai had posted a photo on his Instagram account before the attack, showing himself with two weapons that he was believed to have used. There was no immediate claim of responsibility for the attack.

LAST OUTING BEFORE CURFEW

Witnesses described crowds being fired on in bars as people enjoyed a last evening out before the start of a nationwide coronavirus curfew. Six locations in central Vienna were attacked, starting outside the main synagogue, which was closed.

Nehammer had said overnight that at least one attacker was still on the loose. On Tuesday morning officials appeared to play down that suggestion, saying it was only a possibility but that they could not rule it out.

Officials said the perpetrator had been armed with an automatic rifle, a hand-gun and a machete. Nehammer told APA news agency that 15 properties had been searched.

Austrian media quoted police as saying two arrests had been made in the nearby town of St Poelten.

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APA quoted police as saying two arrests had been made in the nearby town of St Poelten. The Kurier news site reported that heavily armed police had searched two properties.

'Attack on our values'

A witness, Vienna rabbi Schlomo Hofmeister, said he could not be certain whether there was more than one shooter.

"I saw one person. Later, I saw videos and I'm not sure it was the same one. I find it very difficult to identify someone in a fraction of a second," Hofmeister told Reuters television.

"At that moment I also did not pay attention to what he looks like. I was trying to understand what's happening. I then moved away from the window and called the police."

Seven of the injured were in a life-threatening condition, the APA news agency said.

A police spokesman said at least 1,000 officers were involved in the search.

The government announced three days of national mourning, and a minute's silence at noon. (1100 GMT)

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Opera guests leave the state opera under the supervision of armed policemen, in the center of Vienna on Nov 2, 2020, following a shooting (JOE KLAMAR / AFP)

APA reported that multiple homes had been searched and arrests made, citing the Interior Ministry. A Ministry spokesman was not immediately available to comment.

Police officers stay in position at stairs named Theodor Herzl Stiege near a synagogue after gunshots were heard, in Vienna, Nov 2, 2020. (RONALD ZAK / AP)

Sheltering in bars

Police sealed off much of the historic center of the city overnight, urging the public to shelter where they were. Many sought refuge in bars and hotels, while public transport in the area was shut down.

Oskar Deutsch, head of Vienna's Jewish community, which has offices adjoining the synagogue on a narrow cobbled street dotted with bars, tweeted that it was not clear whether the synagogue or offices had been a target.

Videos circulated on social media of a gunman running down a cobbled street shooting and shouting. One showed a man gunning down a person outside what appeared to be a bar on the street where the synagogue is located.

Vienna had been spared the kind of deadly militant attacks that have struck Paris, London, Berlin and Brussels, among others, in recent years.

Condolences poured in from leaders around the world.

Armed policemen patrol near the state opera in the center of Vienna on Nov 2, 2020, following a shooting. (JOE KLAMAR / AFP)

President Emmanuel Macron of France, which has seen two deadly knife attacks in Paris and Nice in recent weeks, issued a statement expressing shock and sorrow.

"This is our Europe," he said. "Our enemies must know with whom they are dealing. We will not retreat."

US President Donald Trump tweeted that "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. The stands with Austria, France, and all of Europe in the fight against terrorists, including radical Islamic terrorists."

Democratic presidential candidate Joe Biden condemned what he called a "horrific terrorist attack", adding: "We must all stand united against hate and violence."

In 1981, two people were killed and 18 injured during an attack by two Palestinians at the same Vienna synagogue. In 1985, a Palestinian extremist group killed three civilians in an attack at the airport.