At least two people are dead, including an attacker, and 15 people were injured after a shooting in six different locations in the Austrian capital of Vienna.
Security officials are calling it a "terror attack" and a huge police operation is ongoing in the city.
Austria’s top security official said authorities believe there were several gunmen involved and police continue to search for the other attackers.
“We are victims of a despicable terror attack in the federal capital that is still ongoing,” Austrian Chancellor Sebastian Kurz said hours after the gunfire erupted.
“One of the perpetrators was neutralised, but several perpetrators appear to still be on the loose,” he said.
“They seem to also, as far as we know, be very well equipped, with automatic weapons. So they were very well prepared.”
Gunmen opened fire on people enjoying a last evening out in Vienna before a coronavirus lockdown.
“It appears to have been a terror attack,” Interior Minister Karl Nehammer told public broadcaster ORF, adding that the perpetrators were armed with rifles.
He said the army had been asked to guard key locations in the city to allow police officers to pursue the attackers.
Vienna Mayor Michael Ludwig said 15 people were taken to hospital, seven with serious injuries.
Vienna Police say an officer is among the injured and that one suspect was shot dead.
“I am glad that our police were able to neutralise one of the attackers,” Austrian Chancellor Sebastian Kurz said.
“We will not never allow ourselves to be intimidated by terrorism and will fight these attacks with all means.”
The force tweeted at 11.20pm local time (10.20pm GMT) warning the situation is "still active" and that the public should stay home.
It said: "If you're on the Streets, take shelter! Keep away from public places, don't use public Transportation!"
Several shots were fired at 8pm local time by several suspects armed with rifles, with the first reported at Seitenstettengasse.
One shooting took place near a synagogue but it was not clear whether the house of worship had been targeted, Oskar Deutsch, the head of the Jewish community in Vienna, said.
The synagogue was already closed at the time of the shooting, Deutsch tweeted.
Resident Natascha Strobl describes the scene from the Austrian capital
Rabbi Schlomo Hofmeister said 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,” 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.”
Police said the operation in the centre of the city was ongoing and urged people to avoid all open spaces and public transport.
Officers said trams and buses were not stopping in the city centre, and urged social media users not to post videos of the police operation, so as not to endanger officers.