“I am deeply shocked by the terrible attacks that took place in Vienna tonight.
The thoughts of Great Britain are now with the people of Austria - we stand shoulder to shoulder with you in the fight against terror, ”Johnson wrote on Twitter.
Earlier it became known that in hospitals after the shooting in Vienna there are 15 victims.
According to police, the attacks took place in six parts of the city.
Austrian Chancellor Sebastian Kurz called the Vienna shooting a horrific terrorist attack.