Austria’s top security official says several people have been injured in an attack in Vienna and there may be fatalities, according to the Austria Press Agency.

APA quoted Karl Nehammer as saying that authorities believe there were several attackers involved and the incident is ongoing. APA earlier cited Mr Nehammer’s office saying one attacker had been killed and another could be on the run.

Police in the Austrian capital urged people to avoid all open spaces and public transport in the city. Police said trams and buses were not stopping and urged social media users not to post videos of the police operation, so as not to endanger officers.

“There are several injured persons,” police tweeted. “We are on site with all available forces. Please avoid all public squares in the city.”

There is a larger police operation going on in the 1st district of Vienna (Inner City area). Officers are on site and check the Situation. We keep you posted on the matter.

— POLIZEI WIEN (@LPDWien) November 2, 2020

Oskar Deutsch, the head of the Jewish community in Vienna, said the shooting took place in the street where the city’s main synagogue is located but it was not clear whether it had been targeted.

The synagogue was closed at the time of the shooting at around 8pm local time, he tweeted.

Rabbi Schlomo Hofmeister told the Associated Press that he saw at least one person fire shots at people sitting outside bars in the street below his window.

“They were shooting at least 100 rounds just outside our building,” Mr Hofmeister said.

“All these bars have tables outside. This evening is the last evening before the lockdown,” he added.

“As of midnight, all bars and restaurants will be closed in Austria for the next month and a lot of people probably wanted to use that evening to be able to go out.”