Three people were killed and 34 were injured Saturday when a "mentally unbalanced" man drove a 4x4 into a street thronged with shoppers in the southern Austrian city of Graz, a local official said.
Witnesses said the car was travelling at over 100 kilometres (60 miles) per hour when it hurtled onto Herrengasse, one of the main pedestrian shopping streets in Austria's second largest city, the local APA news agency reported.
The 26-year-old driver was detained after losing control of the vehicle, said governor Hermann Schuetzenhoefer, who described the man as "mentally unbalanced".
Ten of the injured were seriously injured, one of whom was in life-threatening condition, Schuetzenhoefer added.
Regional police chief Josef Klamminger ruled out a terrorist motive.
APA cited a police source as saying the driver showed symptoms of "psychosis".
President Heinz Fischer said he was "deeply shocked" by the attack.