At least seven people have been injured by a driver who drove on a footpath in the northern Italian city of Modena on Saturday and then got out wielding a knife, according to authorities.The man, a 31-year-old Italian citizen of Moroccan origin, accelerated suddenly then zigzagged erratically on Via Emilia around 4:30 pm, mowing down multiple pedestrians, The NY Post reports, citing officials.“He was going at least a hundred kilometres per hour, we saw people flying,” one witness told Il Messagero.Mayor Massimo Mezzetti said that four of the seven hit had been seriously injured.The driver “aimed for the sidewalk, hitting a bike, then crashed while slamming head-on into a woman, badly hurt with both legs crushed”, Mr Mezzetti told local media and the ANSA news agency. He crashed the vehicle into a storefront window, crushing one woman between the car’s front end and the shop. She was taken to hospital in critical condition, and will likely have both legs amputated, authorities said.After crashing, the suspect allegedly tried to run and stabbed at least one person before he was chased down by bystanders and stopped.Police have arrested the driver and are questioning him, Mr Mezzetti said.The victim, identified by Italian media as Luca Signorelli, was stabbed as he chased down the suspect.“He disappeared behind a row of cars and then suddenly reappeared with a knife in his hand,” Signorelli told reporters, his head still dripping with blood.“He was babbling something, but it wasn’t Italian. Two slashing blows came at me—one aimed at the heart, the other at the head. A scuffle broke out,” he recounted.“I managed to dodge one of the strikes, but the other one hit me. Then I pinned his wrist. And then I neutralised him.”In all at least seven people have been injured, according to the mayor.The motive is not yet known, but a terrorist attack is not being ruled out, Italian newspaper La Pressa is reporting.“We need to understand what’s behind this act. But it was a dramatic event. I am deeply shaken. Whatever it was, it was extremely serious. If it turns out to be an attack, that would be even more serious,” Mr Mezzetti said.- With AFP