The officer sustained an injury in the head at the Flatbush Avenue station.
He was taken to the hospital with a non life threatening injury. A suspect was taken into custody.
The power to the tracks was shut and subway service was disrupted while police searched for the suspect.
Southbound number 2 trains are terminating at President St, southbound 5 trains are terminating at Bowling Green, due to a police investigation at Flatbush Avenue.
The investigation continues.
