A seven-year-old girl was shot and killed in Detroit when an officer's gun went off during a struggle with a woman in a house where police were searching for a suspect in the slaying of a teenager, a police official said.

Assistant Chief Ralph Godbee said at a news conference Sunday that Aiyana Jones was hit in the neck by a single bullet and died at a hospital.

"This is any parent's worst nightmare. It also is any police officer's worst nightmare," Godbee said.

Godbee said officers with the department's Special Response Team set off a flash grenade as they entered the home about 12:40 a.m. Sunday with a warrant to look for a suspect in the Friday slaying of a 17-year-old boy.

The lead officer encountered a 46-year-old woman immediately inside the front room of the house and "some level of physical contact" ensued, during which the officer's gun went off, Godbee said.

The officers had identified themselves as police, he said.

'We cannot undo what occurred'

Godbee said the shooting was being investigated and all information was preliminary.

"We cannot undo what occurred this morning," he said. "All we can do is to pledge an open and full investigation and to support Aiyana's family in whatever way they may be willing to accept from us at this time."

The officers had a search warrant and were looking for a 34-year-old man suspected in the shooting death of 17-year-old Jarean Blake.

Blake, a student at Southeastern High School, was gunned down Friday near a store and in front of his girlfriend.

Blake stumbled across the street, collapsed and died, police said.

Officers arrested the suspect inside the home where Aiyana was shot, Godbee said.

"This is a tragedy of unspeakable magnitude to Aiyana's parents, family and all those who loved her," Godbee said. "It is a tragedy we also feel very deeply throughout the ranks of the Detroit Police Department."