Armed policemen stand guard in front of the main entrance to the State Opera in the center of Vienna on November 2, following a shooting.

A huge manhunt was underway on Tuesday after gunmen opened fire at multiple locations across central Vienna, killing at least two people and wounding several more in what Austrian Chancellor Sebastian Kurz describes as a "repulsive terror attack."

One of the gunmen was shot dead by police who said they were hunting for at least one more assailant still at large.

The attacks, in six locations including near a synagogue in the center of the city, were carried out by "several suspects armed with rifles," police said on Monday night.

The shooting began just hours before Austria was to reimpose a coronavirus lockdown, with people out in bars and restaurants enjoying a final night of relative freedom.

Police initially said one person had been killed by the gunman, with public broadcaster ORF describing them as a passer-by.

Vienna Mayor Michael Ludwig later told ORF that a second person had died of her injuries, and that 15 people had been taken to hospital, seven of them seriously wounded.

Police said that an officer had also been hurt during the attacks.

The attacks started at around 8pm (7pm GMT) when the first gunshots were heard in the city's centrally located first district.

In a press conference in the early hours of Tuesday, Interior Minister Karl Nehammer said: "According to what we currently know, there is at least one attacker who is still on the run."

It was unclear how many assailants were involved in the assault.

Speaking to ORF, Austrian leader Kurz said the attackers were "very well equipped with automatic weapons" and had "prepared professionally."

Earlier, he tweeted: "Our police will act decisively against the perpetrators of this repulsive terror attack," adding that "we will never be intimidated by terrorism and we will fight this attack with all means."

Kurz said that while police were concentrating on the anti-terror operation, the army would take over the security of major buildings in Vienna.

Nehammer urged Vienna residents to remain in their homes and keep away from all public places or public transport. He said that children would not be expected to go to school on Tuesday.

Sirens and helicopters could be heard in the city center as emergency services responded to the attack.

An AFP photographer said that large numbers of police were guarding an area near the city's world-famous opera house.

The location of the initial shooting was close to a major synagogue.

The president of Vienna's Jewish community Oskar Deutsch said that shots had been fired "in the immediate vicinity" of the Stadttempel synagogue, but added that it was currently unknown whether the temple — closed at the time — had been the target of an attack.

'Cowardly act'

"It sounded like firecrackers, then we realized it was shots," said one eyewitness quoted by ORF.

A shooter had "shot wildly with an automatic weapon" before police arrived and opened fire, the witness added.

In the busy bars and restaurants, people were told to remain indoors.

"At the beginning, I thought to myself that maybe we were making an American film or that they had drunk too much," said waiter Jimmy Eroglu, 42.

But then he heard shots. "The police came in and said, 'you all have to stay inside because there's a probably a dead man there'."

Robert Schneider, who lives in central Vienna, went out and found two lasers trained on his chest.

"Hands up, take off your jacket," officers shouted at him, the 39-year-old told AFP. "We had seen nothing, heard nothing. We are in shock."

Austria had until now been spared the sort of major attacks that have hit other European countries.

President Emmanuel Macron of France, which has experienced two serious attacks in recent weeks, tweeted that "we French share the shock and sorrow of the Austrian people."

"After France, it's a friendly nation that has been attacked," he added, referring to the killing on Thursday of three people by an attacker in the southern city of Nice and the beheading of a schoolteacher by a suspected Islamist outside Paris several days before.

EU Council Chief Charles Michel tweeted that the bloc "strongly condemns this cowardly act," with European and global leaders also voicing support for Austria.

Czech police said they were conducting checks on the border with Austria.

"Police are carrying out random checks of vehicles and passengers on border crossings with Austria as a preventive measure in relation to the terror attack in Vienna," Czech police tweeted.