A man rammed a car into pedestrians and Christmas shoppers in a bustling area of Australia’s second-largest city, injuring at least 18 other people in an act police said was deliberate.

Police in Melbourne said they arrested the 32-year-old male driver of a white four-wheel-drive Suzuki at the scene, along with another man who was later released. Four people were critically wounded on Thursday, said Daniel Andrews, premier of Victoria state, and another 15 including the driver are in stable condition. Police said the incident...