VIENNA:Three people have died after multiple gunmen opened fire across central Vienna on Monday, and at least one attacker remained on the run after what Chancellor Sebastian Kurz described as a "repulsive terrorist attack".

Interior Minister Karl Nehammer warned people to stay away from the centre of the city, as officials said border checks were being reinforced and that children would not be required to attend school on Tuesday.

Nehammer said at the start of the news conference that "several" people had been killed. An official later clarified that two people were dead, a civilian and a suspected attacker.

Vienna Mayor Michael Ludwig later told broadcaster ORF that a second civilian had died.

"We have brought several special forces units together that are now searching for the presumed terrorists. I am therefore not limiting it to an area of Vienna, because these are mobile perpetrators," Nehammer earlier told broadcaster ORF.

Kurz said the army would protect sites in the capital so the police could focus on anti-terror operations. Speaking to ORF, he said the attackers "were very well equipped with automatic weapons" and had "prepared professionally".

Police said on Twitter that at least one person had been killed and that the injured included a police officer. Vienna mayor Michael Ludwig told ORF that 15 people were being treated in Vienna hospitals, and that seven were in a serious condition.

Police also said they had shot dead one of the attackers.

Nehammer said all six locations in the attack were near the street housing the central synagogue.

Jewish community leader Oskar Deutsch said on Twitter it was not clear whether the Vienna synagogue and adjoining offices had been the target and said they were closed at the time.

Rabbi Schlomo Hofmeister told London's LBC radio he was living in the compound of the synagogue. "Upon hearing shots, we looked down (from) the windows and saw the gunmen shooting at the guests of the various bars and pubs," he said.

"The gunmen were running around and shooting at least 100 rounds or even more in front of our building," he said.

Videos circulated on social media of a gunman running down a cobblestone street shooting and shouting. Reuters could not immediately verify the videos.

ATTACKERS' IDENTITY UNKNOWN

The attack happened hours before a partial lockdown was due to go into place due to the rising spread of the coronavirus, with restaurants, cafes and hotels shuttered and restrictions on movement at night.

Authorities gave no indication of the identity of the assailants or reason for the attack.

"We really can't say anything about the background yet," Kurz told ORF. "Of course an anti-Semitic background cannot be ruled out."

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."

French officials have ramped up security since the attacks in Paris and Nice, which had suspected Islamist motives. Macron has deployed thousands of soldiers to protect sites such as places of worship and schools, and ministers have warned that other Islamist militant attacks could take place.

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.

In recent years, Austria has been spared the sort of large-scale attacks seen in Paris, Berlin and London.

In August, authorities arrested a 31-year-old Syrian refugee suspected of trying to attack a Jewish community leader in the country's second city Graz. The leader was unhurt.