The incident occurred in Derby, north of Birmingham, on Saturday evening. Police said that "several" people had been hit, and a man in his 30s was arrested.
On Sunday, Derbyshire police announced that seven people had been injured.
"The seven sustained various types of serious but not life-threatening injuries," Derbyshire police wrote on Facebook.
An eyewitness described horrific scenes.
"It was such a terrifying experience. We came around a corner and suddenly there were people everywhere," the witness told the Derby Telegraph newspaper.
The man arrested is suspected of attempted murder and reckless driving, among other offences. The motive remains unclear.
