Nearly half the 19 people injured when a driver with no known extremist links plowed into pedestrians in the southern city of Melbourne were foreign nationals, Australian Prime Minister Malcolm Turnbull said Friday.

Police allege that the 32-year-old Australian man, a refugee from Afghanistan, had a history of mental illness and drove a car into Christmas shoppers on one of the busiest roads in Australia's second-largest city on Thursday.

The incident was a chilling reminder of attacks using vehicles in cities around the world. Four people were killed in a similar incident in Melbourne in January.