Eight people were injured, two seriously, on Saturday after a car rammed into a group of pedestrians in the northern Italian city of Modena.

Police said the driver, in his 30s, had been arrested. He is also alleged to have attempted to stab a passerby who had tried to stop him from fleeing the scene.

According to reports in the Italian press, the car crashed into a shop window after hitting the pedestrians on a road in the central area of the city.

The driver is alleged to have “aimed for the pavement, hitting a bike” before crashing “head-on” into a woman, the Modena mayor, Massimo Mezzetti, told the Ansa news agency. The mayor said the woman’s legs were crushed on the impact.

The driver is an Italian national born in the Lombardy city of Bergamo and of north African origin, the mayor said, adding that he lives in the Modena area.

The two seriously injured pedestrians were taken to Maggiore hospital in Bologna.

Mezzetti said the circumstances of the incident were still unclear.

Italian press reports said four or five people had helped to capture the driver after chasing him. One man told Ansa that he disappeared behind parked cars before reappearing, allegedly “with a knife in his hand”.

Mezzetti said “he was seen with a knife in his hand, but he didn’t manage to stab anyone. It seems like he was trying to hit someone”. He added: “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.”

The mayor said he wanted to thank the people who helped to capture the driver, saying “they showed courage and great civic sense”.

One of the injured pedestrians told Rai news that he saw the car crash on to the pavement “at high speed” and heard the sound of “people being hit”. “It was coming in the same direction as me, and I managed to jump out of the way,” he said. The man added that the driver appeared to be under the influence of alcohol or drugs, although authorities haven’t confirmed this.

In a message posted on social media, Italy’s prime minister, Giorgia Meloni, expressed her solidarity “with those who were injured and their families”.