A Triborough Bridge and Tunnel Authority officer accidentally fired a bullet yesterday, sending a colleague to the hospital, authorities said.

She was taking her gun out of her locker when the firearm accidentally discharged a round, sources said.

It hit a locker, and a flying piece of metal hit the other officer in the stomach during the 3 p.m. mishap in the service building of the RFK/Triborough Bridge.

The injured officer is in stable condition at Harlem Hospital.

VIDEO: COP SHOOTS COP