PHILADELPHIA (CBS) — Police say a pit bull was shot dead by police after the dog attacked an officer in the Grays Ferry section of the city.

Chopper 3 was over the scene of the incident on the 1500 block of S. Corlies Street Tuesday afternoon.

Police say they shot the pit bull to prevent further injury to the officer.

The officer was taken to Presbyterian Hospital. Their condition is unknown.

Authorities say one person is in custody. The reason why is unclear at this time.