One of the suspected attackers was also shot and killed, police added.
Austria’s Interior Minister Karl Nehammer has described the incident as a “terror attack,” and urged members of the public to stay indoors, as police try to find the attackers.
Gunfire erupted in the Austrian capital on Monday night, just hours before the start of a nationwide lockdown to combat a resurgence of Covid-19.
In a statement, police said there were several suspects “armed with rifles” and six different shooting locations. Multiple people have been injured in the city center.
“All possible forces” are responding to the incident, according to police, who are urging people to avoid the area and not to share photos or videos on social media.
The area where the shooting took place is a busy district packed with bars and restaurants, near Vienna’s main synagogue, Seitenstettengasse Temple.
Oskar Deutsch, the head of Vienna’s Jewish community, said in a tweet that it was unclear whether the synagogue was a target, but that it was closed at the time of the shooting.
The inner city was packed ahead of the midnight start of the lockdown, and footage shared on social media showed people running away from the scene.
This is a developing story, updates to follow