A man has driven his car into pedestrians in the northern Italian city of Modena, injuring eight people, four seriously, officials say.
They include a woman who reportedly had both her legs crushed.
Passers-by gave chase and managed to detain the man, in his 30s, and hand him over to police.
Prime Minister Giorgia Meloni described the incident as “extremely serious”. City Mayor Massimo Mezzeti added that it would be “even more serious” if it turned out to be a premeditated attack.
The incident occurred around 16:30 (14:30 GMT), when the speeding car hit the pedestrians in the centre of Modena, south-east of Milan.
“We saw the car approaching, it was heading for the curb,” an eyewitness said.
“It suddenly accelerated – it was going at least 100km/h (62mph).”
“We saw people flying,” the witness told Italian media.
Modena’s mayor said it appeared the driver “deliberately drove on to the pavement, hitting several people and crashing into a shop window”.
“He then got out of his car and brandished a knife,” Mezzetti said.
One man who tried to stop him was lightly injured before others joined him to overpower the attacker.
The mayor said the suspect was an Italian national born in Bergamo, “but of Maghreb origins”. He lives in the province of Modena.
Italy’s far-right Deputy Prime Minister Matteo Salvini named the suspect on X as Salim El Koudri.