Police say a family of six was killed and an officer was injured when a car and a cruiser collided at an intersection northwest of Ohio's capital Columbus.

Investigators said an officer from the suburb of Upper Arlington was responding to an armed robbery report at a fast-food restaurant when the crash occurred around 1:30 a.m. ET Friday.

The cruiser was one of an unspecified number of police cars responding to the robbery report, all with their lights on and sirens activated, Upper Arlington police officer and spokeswoman Heather Galli said.

'That car was just totalled'- Police Chief Robert Oppenheimer

The collision happened at a large intersection with traffic lights.

A Columbus man was driving the other car, with his wife in the front passenger seat and four daughters, including a toddler, in the back seat, said Chief Robert Oppenheimer of Perry Township police, who are investigating the crash.

None was wearing a seatbelt, and the youngest daughter was not in a child restraint, he said.

Oppenheimer identified them as driver Eid Badi Shahad, 39; Entisar W. Hameed, 31; Shuaa Badi, 16; Amna Badi, 14; Ekbal Badi, 12; and Lina Badi, 2.

"That car was just totalled, and they probably died instantly," Oppenheimer said.

Franklin County coroner Jan Gorniak said an autopsy could be performed on the driver as soon as Friday. She said autopsies won't be performed on the passengers because of religious objections.

Officer in shock

A small shopping centre sits on one side of the intersection, with a park and river on the other side. The intersection is frequently busy during the day, with hundreds of cars passing through it.

The officer, who had been travelling alone, was being treated for a serious head injury at a hospital but was in stable condition, said Jason Pappas, head of the local police union.

Upper Arlington police identified the officer as Shawn Paynter, who joined the department five years ago and had been on the overnight shift for about a year.

Oppenheimer said the officer was in shock after learning about the deaths, and he had not been interviewed by investigators by midday Friday. That was expected to happen later with his attorney present.

Oppenheimer said a Columbus police accident investigation team will help pull speed and braking data and dash-camera video from the cruiser that could explain more about how the crash occurred.

"We just don't know anything about the condition of the intersection at the time of the accident," he said. "We've had no witnesses step forward. The only thing we have is the driver of the cruiser, and he's in the hospital, and we're unable to talk to him at this time."