An officer from the Columbus suburb of Upper Arlington was responding to a robbery report when the overnight crash occurred at an intersection, said Jason Pappas, head of the local police union. The officer apparently had his vehicle's police lights and siren on at the time, Pappas said.
He said six people in the other vehicle died, including a small child. The officer was being treated for a serious head injury at a hospital but was in stable condition.
Columbus media reported that a male driver and five female passengers were killed, and police believe none of them was wearing a seatbelt. Their names and ages weren't immediately released.
A message was left for Perry Township police, who are handling the investigation and remained at the scene Friday morning.
The crash closed the intersection along a major commuter route, and it was expected to remain blocked for the morning rush hour.